Fulfill the promise, surely (every) promise shall be questioned about

There are authentic traditions to this effect from Abdul Azeem where he quotes that Imam Ja'far as-Sadiq (a.s.) has proved it to be a Greater sin with the help of the following verse of Holy Quran: 
"And those who break the covenant of Allah after its confirmation and cut asunder that which Allah has ordered to be joined and make mischief in the land; (as for) those, upon them shall be curse and they shall have the evil (issue) of the abode." 
(Surah Ra'd 13:25)

The Holy Quran denounces the breaking of promise in the following ayat too: 
"Yea, whoever fulfills his promise and guards (against evil) - then surely Allah loves those who guard (against evil).

(As for) those who take a slender price for the covenant of Allah and their own oaths - surely they shall have no portion in the hereafter, and Allah will not speak to them, nor will He look upon them on the Day of Resurrection nor will He purify them, and they shall have a painful chastisement." 
(Surah Ale-Imraan 3:76-77)

Similarly we find another verse of the same connotation: 
"Surely the vilest of animals in Allah's sight are those who disbelieve, then they would not believe.

Those with whom you make an agreement, then they break their agreement every time and they do not guard (against punishment)." 
(Surah Anfal 8:55-56)

This ayat is critical of the Jews of Bani Qurayza, who did not honour the pact, which they had formed with the Holy Prophet (s.a.w.s.) regarding cooperation with the infidels. They supplied arms to the disbelievers of Mecca for the Battle of Badr and thus invalidated the pact. Later they justified their action saying they had forgotten the pact.

They once more entered into a pact with the Holy Prophet (s.a.w.s.) only to violate it at the time of the Battle of Khandaq (trench). They went against the pact and sided with Abu Sufyan.

In various places in the Holy Quran we find that fulfilling a promise has been made obligatory and highly emphasised.

For example, 
"and fulfill the promise, surely (every) promise shall be questioned about." 
(Surah Bani Israel 17:34)

Also, 
"O you who believe! Fulfill the obligations." 
(Surah Maidah 5:1)

Similarly in Surah Baqarah the ayat says, 
"...and the performers of their promise when they make a promise..." 
(Surah Baqarah 2:177)

We also find the following verse: 
"O you who believe! Why do you say that which you do not do?

It is most hateful to Allah that you should say that which you do not do." 
(Surah Saff 61:2-3)

Imam Ja'far as-Sadiq (a.s.) has explained this ayat in the following manner: 
"A believer's promise to his believing brother is a vow that has no expiation (It cannot be broken). But one who goes back on his word declares his opposition and enmity to Allah, and invokes the anger of Allah." 
(Wasaelush Shia)

After this the Imam (a.s.) recited the above-mentioned ayat.

Amirul Momineen Ali (a.s.) advises Malik al-Ashtar regarding the honouring of promises: 
"Breaking a promise causes the anger of Allah." 
(Nahjul Balagha)

Ali (a.s.) also quotes the same verse after this. 
Hazrat Imam Muhammad al-Baqir (a.s.) said: 
"There are four types of sinners who are punished very soon:
a) The person who violates the pact that he has made with you, even though you have respected it. 
b) One who inflicts harm upon you even though you caused him no harm. 
c) One who has promised you something and you are faithful upon your agreement but he is unfaithful. 
d) One who wants to severe relations even though the relative wishes to continue the relationship."
(Khisaal)

Abu Malik inquired from Imam Zainul Abedin (a.s.), "Inform me about all the rules of religion." Imam (a.s.) told him, 
"To speak the truth, to judge with justice and to fulfill the promise." 
(Khisaal)

Although a vast number of traditions and ayats denounce the breaking of promises. We shall quote some selected ones.

Types of Promises

There are three types of promises:
1. Promise of Allah to His creatures. 
2. Promise of the creatures to Allah. 
3. Promises of the people among themselves.

The promise of Allah to His creatures is that of the Aalam-e-Zar (in the spiritual plane). We come to know of this promise through the Quranic ayats as well as the traditions. According to this, Allah first created the souls of all human beings and made the following covenant: That they remain upon the right path, do not associate anyone or anything with Allah, obey the commands of their Prophet, and do not follow Shaitan, Allah shall recompense them by helping them, by keeping them forever in His mercy, and give them a place in Paradise but if they do not respect their covenant, Allah will also disregard His side of the promise. It is for this very fact, that Allah says.

"...and be faithful to (your) covenant with Me, I will fulfill (My) covenant with you." 
(Surah Baqarah 2:40)

Allah also says, 
"Did I not charge you, O children of Adam, that you should not serve the Shaitan?" 
(Surah Yaseen 36:60)

The covenant that Allah took from the people in the spiritual plane also includes the oath with regard to the Wilayat (Mastership) of Amirul Momineen Ali (a.s.) and the Imams (a.s.). Numerous traditions mention this fact. It is even recorded in the various heavenly scriptures, and all the Prophets have conveyed the message of the Wilayat of the Fourteen Masoomeen (a.s.).

However, some scholars have rejected this concept of the Aalam-e-Arwah or Aalam-e-Zar. They give a different explanation to the traditions and ayats that deal with this subject. According to them Aalam-e-Arwah (the spiritual plane) is essentially the innate human nature, which is so designed by Allah (a.j.) that it is desirous of obeying Allah's command and does not desire to follow Shaitan. Of course the reasoning capacity of man directs him to follow his nature and accordingly obey Allahs orders. Hence if a man goes against Allah's command he goes against his own nature. These thinkers consider the covenant, to be the same as the innate nature given to us by Allah (a.j.). This book is not concerned with the detail of these two theories.

Anyway whether a man breaks the promise given in Aalam-e-Zar, or goes against his innate nature, he commits a greater sin. This fact has been emphasised in most ayats and traditions, and it is confirmed that honoring the covenant is wajib and not respecting it is haraam. It is also confirmed that the breaking of this first covenant can bring severe chastisement. The people are also warned of dire consequences in case of default. The traditions also inform us that serious retribution incured just for violating the first covenant, which is the greatest of the sins. Hence it is incumbent upon the people to fulfill their covenant so that Allah may also fulfill His promise.

Allah has promised to answer every prayer

One of the promises of Allah to His creatures is that He will answer every prayer, but this is only on condition that the supplicant honors this covenant with Allah (a.j.).

Jamil narrates from Imam Ja'far as-Sadiq (a.s.) who said, 
"When a man prays to Allah with a pure intention and a sincere heart, Allah answers (his prayer) after man has fulfilled his promise to Allah (a.j.). But if man prays to Allah without a pure intention and sincerity, Allah does not answer it. Has not Allah said, '...and be faithful to (your) covenant with Me, I will fulfill (My) covenant with you,' so the promise is kept only with one who keeps his own word.'
(Safinatul Behaar)

Verbal expression of a promise

The second type of promise is one that the man himself gives to Allah, like a vow or an oath. For an oath to be binding, it is necessary that it be expressed verbally. For example, if someone wants to vow to Allah and state it in Arabic language he should say 'Aahadto Allah' (I have vowed to Allah) or 'Alayya Ahadollah' (The vow for Allah is upon me). The statement of promise, oath or the vow can be in any language but expressed verbally. A vow for example may consist of saying, "if I return safe and sound from the journey, I shall give such and such amount as charity in the way of Allah."

If an oath is intended mentally and not expressed verbally, it is not binding.

Vow or oath for a useless thing

It must be remembered that a vow, oath or a promise should not be taken for a useless object. That is, the object must not be undesirable from the Islamic point of view. An oath taken to carry out some makrooh or haraam action, a vow to abstain from a wajib or a mustahab act is invalid. An oath taken for an action which is wajib and its avoidence haraam in a prevailing set of conditions, automatically becomes invalid if the conditions change. For example, a man vows to give a thousand rupees in charity if he gets well, but after he is well be becomes so poor that it is hardly possible for him to maintain his family. In these circumstances the vow is considered invalid and it is not wajib on him to fulfill it.

Vow should be for a useful aim

In conclusion it can be said that an oath should be taken if it is acceptable from the Shariat point of view. In any case an oath should be taken when common sense dictates that the oath serves some useful purpose, either by carrying out an action or by abstaining from it. For example to walk and exercise etc. which are beneficient and Mubah (permitted) actions, and to abstain from smoking which is harmful to health although Mubah.

Conditional and absolute covenant

Just as in the case of oath and vow, a covenant is also either conditional or absolute. An example of an absolute covenant is when a man says, "I make covenant with Allah that I shall perform such and such good action." Then this shall become binding upon him. If he does not do so he would have committed a Greater sin. In addition he also has to pay the penalty. The conditional covenant is the one when the person attaches some conditions. For example, he may say, "If Allah gives me a son, I will perform such and such good deed." Then that good deed becomes wajib upon him only when he gets a son. Once the condition is fulfilled it will also be haraam for him to leave the deed undone and he will have to pay the additional penalty also.

Three types of covenant with Allah

Actually a vow and an oath is also a covenant with Almighty Allah. Therefore a covenant is of three types. One is the covenant itself and of the other two one is a vow and the other an oath. It is only due to Divine Mercy that man is given a choice of three kinds of covenants in case he wishes to avoid the risk of being liable for keeping sixty fasts etc. Hence, he can make a vow or take an Islamic oath.

Expiation of a vow or a covenant

Breaking of a covenant, whether absolute or conditional, is haraam. The expiation becomes wajib in case of default. It is the same penalty as that of breaking or omitting, without any reason, a fast of the month of Ramazan, i.e. feeding sixty poor people, keeping sixty fasts or freeing a slave.

If a vow is broken its kaffarah (expiation) is same as that of breaking an oath. That is, feeding, or clothing ten poor people or freeing a slave; but if he cannot do any of these then it is wajib for him to keep three fasts.

Breaking of promise and hypocrisy

Breaking of a promise is a very serious sin. It is a sin that sows the seed of hypocrisy in the heart of the person who commits it. The person dies in a state of disbelief and is raised with the hypocrites on the Day of Judgment. The Holy Quran says: 
"And there are those of them who made a covenant with Allah: If He gives us out of His grace we will certainly give alms and we will certainly be of the good. But when He gave them out of His grace, they become niggardly of it and they turned back and they withdrew. So He made hypocrisy to follow as a consequence into their hearts till the day when they shall meet Him because they failed to perform towards Allah what they had promised Him and because they told lies." 
(Surah Tauba 9:75-77)

The Shaan-e-Nuzool (circumstances of Revelation) of this ayat, according to Tafseer Minhaj us-sadeqeen is as follows: "Thulbe Ibne Khatib was a very staunch and a prominent Christian. One day he came to the Holy Prophet (s.a.w.s.). He began to complain of his poverty, and requested the Holy Prophet (s.a.w.s.) to pray for him. The Holy prophet (s.a.w.s.) advised him, "Do not emphasise upon this prayer of yours but be patient in your circumstances. Too much of wealth is dangerous for you. If you are grateful for this favour it is better than too much of wealth that makes you unthankful. By Allah if I pray that mountains become gold and silver and move with me, Allah shall cause it to be so but I know that an honourable hereafter is better, and those who are well provided in this world have a difficult hereafter. So, follow the Prophet of Allah (a.j.) and accept his advice."

But Thulbe the Christian did not follow the advice of the Holy Prophet (s.a.w.s.) and again he came back to him with his entreaty and said: "O Prophet of Allah! I make a covenant to Allah that if He gives me abundant wealth I shall spend it upon the deserving ones and do good through it."

When he persisted in his request, the Holy Prophet (s.a.w.s.) prayed for the removal of his property.

Allah gave abundant increase in his livestock; and he became a Muslim. His animals multiplied and he became so busy in supervising them that he stopped praying behind the Holy Prophet (s.a.w.s.) in the congregational prayers. He prayed only the morning and the evening prayers. Then his herd became so bulky that the surrounding area of Madinah was not sufficient any more. He took his animals to the outskirts of the town and settled there. Now he was deprived of praying the daily prayers behind the Holy Prophet (s.a.w.s.). Still he continued to come to Madinah for the Friday prayers. Then his business expanded beyond the valleys surrounding Madinah. Finally he could not even attend the Friday prayers.

One day the Holy Prophet (s.a.w.s.) asked his companions, "Why is Thulbe not attending the congregation?" The people replied, "He has so many goats and sheep that a single valley is unable to accommodate them. Now he has moved to such and such valley and settled there. The Holy Prophet (s.a.w.s.) upon hearing this said, 
"Woe be upon Thulbe, Woe be upon Thulbe, Woe be upon Thulbe!"

Later when it was wajib to pay zakat due to the revelation of the verse of Zakat, the Holy Prophet (s.a.w.s.) summoned one of his followers and gave him this verse in writing and sent with him a tribesman of Bani Salim. The Prophet ordered, "After you have collected Zakat from Thulbe go to such and such good man and collect it from him too." Both of them went to Thulbe. They showed him the Quranic verse and also gave him the letter of the Holy Prophet (s.a.w.s.) containing the rules of Zakat. Thulbe had become so much attached to his wealth that he said, "Muhammad is collecting Jiziya from us! Go somewhere else! Meanwhile I shall think upon it."

The two men went to this righteous person (of the tribe of Bani Salim). When he saw the ayat and the letter of the Holy Prophet (s.a.w.s.), he said, "I hear and I obey the command of Allah and the Prophet (s.a.w.s.)."

He went among his camels and selected the best ones for Zakat and said, "Please take these for the Messenger of Allah (s.a.w.s.)." The agents told him that it was not wajib to give the best of the camels. He said, "How can I not offer the best for Allah and His Prophet (s.a.w.s.)?"

Then these two men came back to Thulbe. The wretched fellow repeated his previous objection and refused to pay Zakat.

When the Holy Prophet (s.a.w.s.) heard of this incident he said just once, "Woe be upon Thulbe!" Then the Holy Prophet (s.a.w.s.) prayed for the well being of the one who had paid the Zakat willingly.

The companions used to wonder why Thulbe had not accepted the advice of the Holy Prophet (s.a.w.s.) and saved himself from apostasy! (Zakat is one of the Dhururiyaat-e-Deen and one who says that Zakat is not wajib has apositisised and is no more a Muslim!) The ayats quoted before this discussion were revealed for Thulbe.

Mutual covenants and agreements

The third type of promise is when people form actual covenants and agreements. The ayats and the traditions state that it is wajib to fulfill this type of promise and it is haraam to go against them.

For example in Surah Bani Israel: 
"...and fulfill the promise; Surely (every) promise shall be questioned about." 
(Surah Bani Israel 17:34)

Similarly the Quran describes truthful and the pious people thus,
"...and those who fulfill their promise when they make a promise.." 
(Surah Baqarah 2:177)

Also when describing those who shall be saved from Hell and earn Paradise, Allah says, 
"And those who are keepers of their trusts and their covenant." 
(Surah Momin 23:8)

Imam Ja'far as-Sadiq (a.s.) says, 
"To keep your word to your believing brother is wajib like a vow, even though there is no expiation for going against it."

The Holy Prophet (s.a.w.s.) said: 
"One who has belief in Allah and in last day (Qiyamat) must keep his word when he promises." 
(Usool-e-Kafi)

Thus keeping a promise is a fulfillment for the belief in Allah and the Day of Qiyamat. Similarly, the beginning verses of Surah Saff have also denounced the breaking of promise and clearly prove that non-fulfillment of a promise (of every type) is haraam.

Hypocrites do not keep their words

The Holy Prophet (s.a.w.s.) is reported to have said: 
"Three traits make man a hypocrite even if he prays and fasts:
Betrayal of trust, lying and non-fulfillment of promise." 
(Usool-e-Kafi)

Imam Ja'far as-Sadiq (a.s.) says, 
"Those who are just in their dealing, those who do not lie and those who fulfill their promises are from those who have perfect morals. And it is haraam to criticise them behind their back. Their being just (Aadil) is obvious. To maintain brotherly relations with them is wajib." 
(Usool-e-Kafi)

It follows from this tradition, that a person who is unjust, a liar and one who does not keep his word, does not possess morals. He is not a just person (Aadil) but a transgressor (Fasiq) and it is not wajib to fulfill the rights of brotherhood towards him.

No concession

Imam Ja'far as-Sadiq (a.s.) has also remarked: 
"There are three obligations in fulfillment of which Allah does not give concession to any: To behave well with the parents, whether they are righteous or sinners; to fulfill ones promise; whether to a righteous person or a sinner; and to deliver a trust (to its owner) whether he is righteous or a sinner." 
(Shaykh Sadooq: Khisaal)

Amirul Momineen Ali (a.s.) says: 
"One must also fulfill that promise that he has made to his wife. For a Muslim is always wary of his promise except when it is for making a prohibited thing legal or prohibiting that which is permitted." 
(Tahzeeb)

Treaties with the polytheists

It is an established fact that there are numerous Quranic verses and traditions which prohibit the breaking of a promise, and makes obligatory the fulfillment of promise. The following verses are sufficient to prove this point:
"Surely the vilest of animals in Allah's sight are those who disbelieve, then they would not believe. Those with whom you make an agreement, then they break their agreement every time and they do not guard (against punishment)." 
(Surah Anfal 8:55-56)

Thus those who do not fulfill their promises are the worst of creatures! They are worse than animals. It is also important to know that Allah has ordered us to honour and fulfill even the treaties and promises made with the disbelievers and polytheists. These promises cannot be disregarded.

The Holy Prophet (s.a.w.s.) respected the treaty with the Polytheists of Mecca

When the power and glory of Islam was at its zenith a verse of Surah Baraat was revealed; ordering Jehad (holy war) against the polytheists. The Almighty Allah commanded the Prophet to purify the Holy Mecca from the filth of polytheism and idol worship but it was also ordered not to break the treaty with the polytheists if they did not break it. The ayat is as follows:
"Except those of the idolaters with whom you made an agreement, they have not failed you in anything and have not backed up anyone against you, so fulfill their agreement to the end of their term; surely Allah loves those who are careful (of their duty)." 
(Surah Tauba 9:4)

Abu Rafe says: "The Quraish sent me to the Holy Prophet (s.a.w.s.). When I met him, my heart became illuminated with his countenance. I said to him, "O Prophet of Allah! I do not wish to go back to the Quraish." He said, I would not act against the terms of treaty, and retain their messenger. Abu Rafe, go back to your people now and after this if you wish, you may accept Islam and join us."

Honoring the terms of the treaty with the Quraish

Huzaifa Yamani says that there was one thing that discouraged me from participating in the Battle of Badr. Abu Husael and I were going out when we came face to face with some men from the Quraish. They asked, "Do you love Muhammad?"

"We love Madinah," we replied. 
They made us promise that after reaching Madinah we shall not accompany the Holy Prophet (s.a.w.s.) in the battle. When we met the Holy Prophet (s.a.w.s.) and told him of this promise he said, 
"Do not think of joining in the battle due to this oath of yours. We shall seek the Divine assistance!"

The above two traditions are recorded in the book, "Islam and World Peace" by Syed Qutb, Pg.264.

The Kafir father took away his son

During the treaty of Hudiabiya, Sohail Ibne Umer was representing the disbelievers in negotiating with the Holy Prophet (s.a.w.s.). When it was time for drawing up the treaty and the signatures were yet to be affixed, Jundal the son of Sohail left the pack of disbelievers and went to the Muslims. Seeing that he was attracted to the Muslims, the Quraish chained his legs but he escaped with the chains intact. He went away with the Muslims and began to behave like one. When his father saw this, he came to his son and gave him a resounding slap. Then he told the Holy Prophet (s.a.w.s.), "O Muhammad! This (treaty) is the first step of reconciliation between you and us and as per its terms you have to surrender my son to me."

The Holy Prophet (s.a.w.s.) agreed to it and surrendered Jundal to his Kafir father, but upon the condition that he would be protected and not harmed. Sohail Ibne Umar agreed to this condition. When it was time to hand over Jundal to the disbelievers, Jundal protested, "O Muslims! I have become a Muslim! How will I return amongst the polytheists?"

The Holy Prophet (s.a.w.s.) told him, 
"Go! But have patience. Allah will provide ease to you in this way only. We cannot go against the terms of the treaty."

Sohail caught his son's hand and led him away. He did not remain true to his promise and tortured his son very much.

This incident proves the importance of the fulfillment of a promise. The same incident is mentioned in the exegesis of Surah Fath in Tafseer Minhajus Sadeqeen.

I will stay here all my life

The following narration is recorded in Behaarul Anwaar:
The Holy Prophet (s.a.w.s.) promised a man that he would wait for him at an appointed place near a stone. The Holy Prophet (s.a.w.s.) waited there but the man did not turn up. Morning turned into afternoon while the Holy Prophet (s.a.w.s.) stood in the blazing sun. Some of his followers saw him and said, "Please stand in some other place."

He (s.a.w.s.) replied, 
"I cannot move away from here till that man returns."

The man arrived at last. The Holy Prophet (s.a.w.s.) said, 
"If that man had not come, I would have continued to stand till death!"

Janab-e-Ismail and the fulfillment of the vow

The Holy Quran refers to Prophet Ismail as the "Truthful in Promise," in the following verse:
"And mention Ismail in the Book, surely he was truthful in (his) promise, and he was an apostle, a prophet." 
(Surah Marium 19:54)

Hazrat Ismail (a.s.) had promised to wait for a person, who did not turn up. Three nights passed but he still kept waiting. However, according to most of the scholars and well-known tradition the period of his wait was a whole year. During this time he also had to bear untold difficulties and sometimes survived on leaves.

Violation of a promise is caused by disbelief

Amirul Momineen Ali (a.s.) has mentioned that it is disbelief that causes one to go back on his word and break a vow. He says:
"By Allah, Muawiya is not more cunning than I am but he deceives and commits evil deeds. Had I not been hateful of deceit I would have been the most cunning of all men. But (the fact is that) every deceit is a sin and every sin is disobedience (of Allah), and every crafty person will have a banner by which he will be recognised on the Day of Judgment." 
(Nahjul Balagha Sermon 200)

Allamah Majlisi says that the one who commits greater sins is also referred to as a disbeliever in traditions. Hence every type of a crafty person has been called a Kafir in this sermon. It is that disbelief which has its root in the heart and which takes the form of disobedience to Allah's commands.

A Muslim is never deceitful

Amirul Momineen Ali (a.s.) has said: 
"Surely fulfillment of pledge is the twin of truth. I do not know a better shield (against the assaults of sin) than it. One who realises the reality of return (to the next world) never betrays. We are in a period when most of the people regard betrayal as wisdom. In these days the ignorant call it excellence of cunning. What is the matter with them? Allah may destroy them. One who has been through thick and thin of life finds the excuses preventing him from orders and prohibitions of Allah, but he ignores them despite capability (to succumb to them and follows the command of Allah), while one who has no restraints of religion seizes the opportunity (and accepts the excuses for not following the commands of Allah)." 
(Nahjul Balagha Sermon 42)

Violation of promise and falsehood

Some of the Mujtahids consider violation of a promise to be a kind of falsehood. Especially when at the time of promising, one has no intention of fulfilling it. Thus all the verses and tradition denouncing and prohibiting falsehood also apply here.

If there are some conditions

According to the Fatawa (religious decrees) of the leading Mujtahids, it is wajib to honour the terms and conditions of a transaction and it is obligatory to fulfill them. For example the buyer can put a condition that if the goods are defective he can return them within two months. Or the seller may put a condition that the buyer must not spoil the goods if he wishes to return them. In such situations it is wajib to honour the terms of agreement. Similarly if the landlord has restricted the use of his premises to any one except the tenant, the tenant has to observe the terms faithfully. Both the parties to a transaction have a right to lay down their terms and conditions.

Other Mujtahids state that not only is it wajib to honour the terms and conditions of a transaction but the one who has put them may enforce his rights and insist on the condition being fulfilled. For example if an employee has laid a condition that he shall be paid his salary on the first day of every month, then not only is it necessary to pay him as agreed but theemployee has a right to demand it on that day, and he can even take it without the knowledge of his employer.

At times it may happen that the conditions agreed upon are quite irrelevant to the actual transaction and not directly related to it. Even in these cases it is necessary to fulfill the obligations.

In cases where the terms and conditions are such that the parties consider it better to observe them, these conditions do not contribute a right and it is not wajib to follow them to the letter.

Fulfillment of promise is a must

In all respects, fulfillment of a promise is so much emphasised in the Quranic Verses and the traditions, that one should be extremely cautious in honouring every type of agreement and pledge. If a person has to give a promise under compulsion and he does not wish to become a sinner, he can use words like, 'May be', 'If', or 'Insha-Allah' etc. For example he can say, "Insha-Allah (If Allah wills) I will do this."

To vow or pledge after saying Insha-Allah

It is the opinion of Allamah Hilli, and other Mujtahids agree, that every vow or pledge after uttering Insha-Allah (or its translation in any other language) makes the pledge conditional to the Divine will. Hence it is not strictly wajib to fulfill it. But if it is with regard to some promise or condition (of an agreement), that concerns a wajib act or it is for the avoidance of a haraam act, it has to be observed faithfully, even after uttering Insha-Allah.

It must however be understood that the promise which is made conditional by saying 'Insha-Allah' is not binding, only when the person intends the actual meaning of the term Insha-Allah. That is, he must really mean to subject the matter to Allah's will. If he utters Insha-Allah only for the sake of seeking divine blessings then it is binding upon him to remain firm upon his vows.

It should also be clear that it is not only permitted, to disregard a promise of abstaining from a wajib act or to perform a haraam act but it is infact haraam to fulfill it. For example if one vows to punish his wife or son if they did such and such thing, it is better to disregard such vows and forgive them instead.

The Quran says: 
"And let not those of you who possess grace and abundance swear against giving to the near of kin and the poor and those who have fled in Allah's way, and they should pardon and turn away. Do you not love that Allah should forgive you?' 
(Surah Nur 24:22)

It means that Allah forgives the sins of those who forgive the wrongdoings of others.

Prophet Ayyub (a.s.) and his oath of beating his wife a hundred strokes

In a situation where, one has taken an oath in utmost seriousness to inflict punishment, and one does not wish to go against it, it is better to carry out the oath in a manner that a token punishment is given and the oath is also not violated. For example, Prophet Ayyub (a.s.) saw his wife doing something against his will. He took a vow to hit her a hundred strokes after he recovered from the illness. When he recovered, Allah ordered him, 
"And take in your hand a green branch (with a hundred twigs) and beat her (your wife) with it (once) and do not break your oath." 
(Surah Saad 38:44