When the wayfarer to Allah has announced, by his takbirs, that Allah is greater than any description, and by testifying to His Divinity exclusively confined all attributes and praise, or, actually, every influence and effect, to Allah, and confessed his incapability of managing the amr, and by the testimony to Messengership and Guardianship, he has chosen his comrade and company and adhered to the sacred position of successorship and guardianship -as it is said: "The companion (first) then the journey"  then, with quite an explicit tone, he is to prepare his visible and invisible powers for the Salat, announcing the presence to them by saying: "Hayya 'alas-Salat", (come to the Salat) twice . Its repetition is intended to complete awakening [tanbih] and waking up [iqaz], or one is for the inner powers of the kingdom, and the other is for the outer powers of the kingdom, since they also accompany the salik on his journey, as has already been said, and will follow, too.
In this stage, the discipline of the salik is to tell his heart and powers, even the innermost of the heart, that the time of presence is near so as to prepare himself for that, fully observing the formal and the spiritual disciplines. Then he is to announce the general secret and result of the salat, by the calling: "Hayya 'alal-falah" and "Hayya 'ala khayril 'amal (come to the best of deeds) so as to wake up the fitrat (disposition = nature), because prosperity and salvation are absolute happiness, and all the human beings love absolute happiness by nature. The innate nature [fitrat] is in quest of perfection and comfort. The truth of happiness is the absolute perfection and absolute comfort, and that is brought about in the salat, which is the best of deeds, cordially, formally, outwardly and inwardly. This is because the salat, according to its form and appearance, is a great and comprehensive remembrance and a praise of the Greatest Name, which encompasses all the divine affairs [shu'un]. For this reason, the adhan and the iqamah open with the word "Allah" and end with it, and Allahu akbar (Allah is Greater) is repeated in all stages of the salat, and the three tauhids (professions of the Unity of Allah), which are the delight of eyes of the holy men, are effected in the salat, in which the form [surat] of absolute annihilation and complete return are mixed. According to the interior and the truth, it is ascension to the proximity of Allah, the truth of reaching the Beauty of the Absolute Beautiful and vanishing in that Sanctified Essence, dearly loved by the inborn nature [fitrat]. It is by the salat that the complete calmness, absolute comfort and the complete mental happiness are achieved: "Surely by Allah's remembrance are the hearts set at rest." 
Therefore, the absolute perfection, which is attaining to Allah's Court, joining the Necessary Limitless Sea, discerning the Eternal Beauty, and being immersed in the Sea of Absolute Light, is effected in the salat, in which absolute comfort, complete rest and perfect calmness also appear, bringing about the two corners of happiness. So, the salat is perfect prosperity, and it is the best of the deeds. The salik will have to repeat this divine grace, to remind the heart and to wake up his disposition [fitrat] , and after having it in his heart, his inner nature would attach importance to it and observe it, since it looks for perfection and happiness. The same point is true in respect of the repetition. When the salik reaches this stage, he announces his presence by saying: "qad qamatis-salat" (The salat has just started). Then, he is to see himself at the Presence of the Master of the kings of the worlds of existence and the Sultan of the sultans and the Absolute Great, and to inform his heart about the dangers of the Presence, all of which are due to the incapability and the inefficiency of "the possible", and to feel ashamed of not carrying out the any, approaching, with the steps of fear and hope, towards the Generous. He is not to regard himself possessing travelling provisions and company. He is to see his heart empty of safety, not to think his deeds good ones; rather, worth not a penny. Should this state become firm in his heart, he would hope to get Allah's care: Nor Who answers the distressed one, when he calls unto Him, and removes the evil?' 
Connection and Completion
Muhammad ibn Ya'qub, quoting Abu 'Abdullah as-Sadiq (AS), says: "When you recite the adhan and the iqamah, two rows of angels will perform the Salat behind you, but if you said the iqamah (only), one row of the angels would perform the Salat behind you.',  There are many other hadiths to the same effect, some of which say that the length of each row is as the distance between the east and the west.  Another hadith says that when Imam as-Sadiq (AS) was asked about the length of each row, he said: "The length of the shortest row is as the distance between the east and the west, and the length of the longest is as the distance between the heaven and the earth."  In some narratives it is said that if he said the iqamah without the adhan, an angel would stand at his right side and another at his left side,  and other similar narratives. The difference among the narratives may be due to the difference among the knowledge and the sincerity of the musallin, as can be inferred from some narratives in this respect, such as the narrative concerning performing the salat with the adhan and the iqamah in the desert or wasteland.  In short, when the salik sees himself leader of the salat for the angels of Allah, and his heart as the leader of his visible and invisible powers, and gathers, with the adhan and the iqamah, his visible and invisible powers, together with the angels of Allah, he is to regard his heart -which is the best of the external and internal powers, and the intercessor for the other powers - as to be an Imam. And, as the heart is liable for the recitings of the ma'mumin [musallin] after its leadership, and as their faults are undertaken by it, the salik is to be quite keen and a good observant of its presence, and to completely guard the disciplines of the Sacred Presence, making the most of this Sanctified Meeting, admitting the great importance of the attention and the support of the angels of Allah, taking them to be of the favours of the Real Benefactor, and acknowledging his incapability of giving the due thanks to His Sacred Majesty for these great blessings. Surely He is the Benefactor!
. Wasai'lush Shi'ah, vol. 8, p. 299. "Book of Hajj", chs. on "The Manners of Travel", ch. 30, hadith 11, quoted from al-Barqi's Mahasin, p. 357. Similar concepts are in some other narratives, such as: "Inquire about the company before the journey" as in Nahjul Balaghah, ed. by Faydul Islam, p. 936, and "The company (first), then the journey", in al-Ash'athiyat, p. 164, ch. on "Bad Neighbouring".
. Surah ar-Ra'd: 28.
. Surah al-Naml: 62.
. Furu'ul Kafi, vol. 3, p. 303, "Book of The salat" ch. on "Starting the Adhan and the Iqamah", hadith 8.
. Thawabul A'mal, p. 54, "The reward of the one who performs the salat with the Adhan and the Iqamah", hadith 2.
. Wasa'ilush-Shi'ah, vol. 4, p. 620, "Book of the salat" , chs. on "The Adhan and the Iqamah", ch. 4, hadith 4.
. Ibid., Hadith 9: " O Abu Dharr, your Lord boasts over His angels for three persons: a man in a waste land ..."
The General Secret of the Qiyam
Know that the people of knowledge regard the qiyam (the standing position in the Salat) to be a sign of Unity of Actions. Similarly, they see that the ruku' (bowing in the Salat) refers to the Unity of Attributes, and the sujud (prostration) refers to the Unity of Essence -these will be explained in their proper places. But qiyam's reference to the Unity of Action is in the very standing position as well as in the wordings recited while standing. As to the standing position and its reference to the Unity of Action, it is because it denotes the servant's observation of his duty toward Allah, as well as His position [maqam] of self-Existence, manifested in the Sacred Emanation as a manifestation of Action. In this manifestation the position of Allah's Activeness [fa'iliyat] is displayed, and all the beings are absorbed in the manifestation of Action and perished under the Manifest Majesty. In this instance, the gnostic discipline of the salik is to remind his heart of this divine grace and to give up, as much as he can, his personal individuations [ta'ayyunat=I nafsiyah],and to explain to his heart the truth of the Sacred Emanation, and to bring to the core of his heart the fact concerning Allah's Self-Existence [qayyumiyat] and that the creatures are dependent upon Him. Hence, after the fixation of this fact in the salik's heart, his recitation will be by the tongue of the Haqq ( Allah ), and the praiser [dhakir] and the praised [madhkar] will be the Haqq ( Allah) Himself, and some of the secrets of the Fate will be exposed to the gnostic's heart, and "You are as You praised Yourself'  and "I take refuge in You from You"  will be disclosed to him in some degrees, and the heart of the gnostic will receive some of the secrets of the salat, such as looking at the place of prostration, which is of dust, the principal origin (of man), or subjugating the neck and declining the head, as required, implying humility and destitution of "the possible", and the annihilation under the Might and the Sovereignty of (His) Majesty. "O mankind! It is you who are in need of Allah, and Allah is He Who is the Self-sufficient, the Praised One." 
As concerning the wordings of the recitation being a reference to the Unity of Action, we shall explain that in details when we come to comment on the blessed surah of al-Hamd, insha' allah (Allah willing).
. Of an invocation from the Messenger of Allah (SA) in 324. Misbahush Shari'ah, ch. 5. his prostration. Furu 'ul Kafi vol. 3, p. 'Awaliyul-La'ali, vol. 1, p. 389, hadith 21.
. Ibid. Misbahul Mutahajjid wa Silahul Muta'abbid, p. 308.
. Surah al-Fatir: 15.
On the Disciplines of the Qiyam
These [disciplines] are such that the salik is to consider himself present in the Presence [mahdar] of Allah, and regard the world as His Presence, and himself one of the audience at that gathering, standing before Allah, trying to convey the Greatness of the Present and the Presence to his heart, letting it understand the importance and the significance of supplicating to Allah, the Exalted, and, by thinking and contemplating, before starting the salat, to prepare the heart to understand the importance of the situation, obliging it to humbleness, submission, calmness, fear, hope, humility and modesty till the end of the salat. He is to stipulate that his heart should be keen on observing these affairs, and think about the great holy men and guides, and about their moods and how their conducts with the Master of the kings were, so as to learn a lesson from the Imams of guidance and imitate them as his models, not being satisfied with just knowing the names of the infallible Imams, the date of their birthday, death day, the length of their honourable lives and similar details, which are of little advantage. Actually, he is to go through their biography and godly conducts, in order to find out the method of their worship and how their journey to Allah was carried out, and how their gnostic stations, which can be inferred from their miraculous speeches, were.
It is much regretted that we are negligent, intoxicated by nature, empty self-conceited and the stooges of the vile Satan in all matters, without there being any sign of our getting up from our deep sleep and endless forgetfulness. We get so little benefit from the positions and the knowledge of the Imams of guidance (AS) that it is negligible, satisfying ourselves with the outer appearance of their lives, completely disregarding the objectives for which the prophets have been sent, and, actually, we are covered by the proverb: "To take a swelling for a fleshy".  We shall, therefore, relate some of the relevant narratives, so that some of the believing brethren may have a remembrance. Praise be to Allah and thanks to Him!
Muhammad ibn Ya'qub, quoting Imam as-Sadiq (AS), says: "Whenever 'Ali ibn al-Husayn (AS) used to stand for the salat, his face turned pale. Going down for prostration, he would not raise his head until he was wet with perspiration. " 
On the same authority he says: "My father used to say, when 'Ali ibn al-Husayn (AS) used to stand for the salat, he looked like a trunk of a tree, nothing of which would move unless the wind would move it." 
In al-`Ilal, Aban ibn Taghlib, quoting Muhammad ibn 'Ali ibn al-Husayn, says: "I said to Abu'Abdullah [as-Sadiq] (AS): `I noticed that when 'Ali ibn al-Husayn (AS) stood for the the salat, his color changed.' He said to me: By Allah, 'Ali ibn al-Husayn knew before whom he was standing."' 
In a hadith in Falahus-Sail, on the authority of as-Sayyid 'Ali ibn Tawus, it is said : "... then Abu `Abdullah (AS) said : `The salat will not be complete except for the one who has a full purity and a mature completeness , and is away from temptation and deviation, and knows [Allah] and [so] stands [before Him], submits [to Him] and persists. He, thus, stands between despair and hope, [between] patience and worry, as if the promises to him have been done, and the threats upon him have happened, lowering his fame [`ird] and manifesting his aim. He sacrifices for Allah his soul, treads upon the road to Him as his goal, not unwillingly, severs the relations of interest for the sake of the One to Whom he bounds and comes, and from Whom he seeks help. Should he achieve all these, the salat would be of the ordered type and of the informed about, and it is the very salat which forbids evil and vice." 
Muhammad ibn Ya'qub, quoting our master, Zaynul-`Abidin (AS), says that he said: "As regards the rights of the salat, you are to know that it is a visit to Allah and that in it you are standing before Him. If you realized that, you would deserve to be, through it, in the position of a slave who is humble, desirous, horrified, frightened, hopeful, distressed, imploring, and glorifying the state of the One in front of Whom he stands with complete stillness, solemnity, submissiveness of the limbs, humility, well supplicating to Him for himself, requesting Him to free his neck, which is encircled by his faults and consumed by his sins; and there is no power except by Allah. 
The Prophet (SA) is quoted to have said: "Worship your Lord as if you see Him. If you do not see Him, He sees you." 
In Fiqhur-Rida it is stated: "When you want to perform the salat, do not go to it lazily, sleepy, hurriedly, or unmindfully. You are to approach it calmly, solemnly and slowly. You are also to display submission, imploringly and humbly, to Allah. You are to show awe and sings of fear and hope, with caution and apprehension. Thus, you are to stand before Him, as an escapee and sinful slave stands at attention before his master, on the alert, with joined heels, erected trunk, not looking to right and left, reckoning as if you see Him, and if you do not, He certainly does see you ..." as the hadith goes. 
In `Uddatud-Da`i it is stated: "It is narrated that the imploring moanings of Ibrahim (AS) used to be heard from a mile's distance, such that Allah praised him by saying: "Ibrahim was mild, imploring, penitent."  When performing his salat, a sound of fizz , like that of a boiler, was heard coming from his chest. A similar sound was also heard from the chest of our Prophet (SA). Fatimah (AS) used to pant in the salat because of her fear of Allah."  And there are other similar hadiths.
There are too many noble narratives on these subjects to be covered in these papers. Contemplating these few narratives suffices the people of thought and remembrance, in respect of the formal, cordial and spiritual disciplines, as well as concerning the way of standing before Allah.
Think a little of the conditions of 'Ali ibn al-Husayn, the supplications of that great man and his implorings to Allah, the Exalted; as well as his elegant invocations, by which he taught the disciplines of servitude to the servants of Allah. I do not allege that the supplications of those great men were intended to teach how to worship, for it would be an empty and meaningless statement prompted by being ignorant of the state of Lordship and of the knowledge of Ahlul Bayt (AS). Their fear and awe were much greater than anybody else's, and the Greatness and Majesty of Allah were manifested in their hearts more than in anyone else's heart. I only say that the servants of Allah should learn from them how to worship Allah and how to travel to Him. When you read what they used to say in their supplications and invocations, you should not read them as mere pronunciations of the tongue. They should be pondered upon, and their behaviour with Allah, their displaying humility, inefficiency and destitution, are also to be noted.
By the Beloved! 'Ali ibn-Husayn was one of the greatest blessings which Allah, the Most High, had bestowed upon His servants as a grace, bringing him down from the sacred world of Proximity, for the sake of teaching the ways of servitude to His servants: "Then, on that Day, you shall most certainly be questioned about the bliss".  If we are asked: "Why did you not appreciate the value of that bliss and did not get benefit from that great man?", we shall have no reply but to droop down our heads for being ashamed, and to be burnt with the fire of remorse and regret, when no regret would avail.
A Piece of Good Advice
My dear, now that the chance is available, and you are still in the prime of life, the way of journeying to Allah is open, the doors of His mercy are not closed, the soundness of the organs and powers is obtained and the land of planting [daruz-zar`] in the material world is still there, strive to realize the value of these divine favours in order to be benefited by them. Try to acquire the spiritual perfections and the eternal happiness. Take advantage of all these branches of knowledge which the honourable divine Qur'an and the infallible Ahlul Bayt (AS) have spread in the land of the dark nature, and illuminated the world with their divine bright light. Enlighten the land of your dark nature, as well as your eyes, ears, tongue and your other external and internal powers, with the light of Allah, the Exalted, and change this dark earth to another one, luminous, or rather to an intellectual heaven: "On the day when the earth shall be changed to a different earth",  "And the earth shall beam with the light of its Lord."  On that day, if your earth is not changed to a different one, and if it is not lighted with the light of the Lord, you will encounter darkness, difficulty, horror, pressure, humility and torture.
At present, our external and internal powers are darkened with Satanic darkness. Should we remain so, our material earth with its inborn light will gradually change into a dark dungeon, empty of the inborn light and veiled from the rules of the divine disposition. This is misfortune entailing no happiness, a darkness which comes to no luminosity, a horror which does not see the face of tranquillity, and a torment which has no comfort with it: " ... And to whomsoever Allah does not give light, he has no light."  I take refuge in Allah, the Exalted, from the Satanic conceitedness and from the evil-commanding soul.
The principal objective of the great prophets, of legislating the laws, of establishing the rules and of the coming down of the heavenly books-especially the all-embracing holy Qur'an, the projector of whose pure light is the Seal of the Messengers (SA) - is spreading monotheism and divine knowledge, and uprooting infidelity, atheism, hypocrisy and dualism, for the secret of monotheism and abstraction is flowing in all the cordial and formal worships. The Sheikh, the gnostic and perfect, Shahabadi, [may my soul be his ransom], used to say: "Worship is the operation of tauhid [monotheism] in the kingdom of the body from the inside of the heart."
In short, the sought-for result of worship is acquiring knowledge, confirming monotheism and other knowledge in the heart. This objective cannot be attained except when the salik vindicates his cordial shares of worship, and passes from the shape and form to the core and the truth, without lingering in this world and the surface, for loitering in such affairs is a hindrance [thorn] in the way of mankind. Those who call for the mere external appearance [surat], preventing the people from the internal disciplines, alleging that religion has no meaning and no reality other than its appearance and surface, are but the Satans on the road to Allah, and the thorns in the way of humanity. To be saved from their evil one has to take refuge with Allah, the Exalted, for they extinguish the divine inborn light, which is the light of [divine] knowledge, tauhid, guardianship and other kinds of knowledge, and draw the covers of imitation, ignorance, tradition [`adat] and fancies [auham] on it, deter the servants of Allah, the Exalted, from advancing to His threshold, and from reaching to His Beautiful Beauty, and block the way of knowledge. They direct the pure and sincere hearts of Allah's servants - in which He, with His hand of Beauty and Majesty, hid the seeds of knowledge in their disposition, and sent the great prophets and heavenly Books to breed and bring them up - to the world, to its ornaments, to its materialities and corporalities, and to its falsities, and divert them from spiritualities and intellectual happiness, confining the invisible world and the promised paradises exclusively to food, drink, sex and other animal desires.
They think that Allah, the Exalted, has laid out His table-cloth of mercy, sent down, with so much ceremony, His Books, employed His noble angels and assigned great prophets, just for the sake of satisfying hunger and sex. The most they know is: Take care of your stomach and sex drive so that you may attain to your desire in the other world. The importance which they attach to a sexual intercourse lasting for five hundred years [in Paradise according to a narrative] they do not attach to tauhid and prophethood, and they take knowledge to be a preliminary to satiate their libido and gluttony. If a godly philosopher, or a divine gnostic, wanted to open a door of mercy to the servants of Allah, or to read a paper of divine wisdom to them, they would spare no abuse, curse and forged accusations without throwing them at him. They are so indulged in mundane affairs, and so concerned about sex and stomach, unknowingly, that they do not desire any other happiness in this world except satisfying their animal lust, despite the fact that the intellectual happiness, should they care for it, would not injure their lust for sex and food.
Like ourselves, since we have not yet crossed the limit of animality, we think of nothing but food and sex, to which we may attain by the grace of Allah, the Exalted. We are not, however, to believe that happiness is confined to that, and that the paradise of Allah, the Exalted, is restricted only to this paradise of animals. As a matter of fact, Allah, the Exalted, has such worlds that no eye has ever seen, no ear has ever heard of, and never occurred to any heart. Yet, the people of divine love and knowledge pay attention to none of those paradises, and are interested in neither of the invisible and visible worlds. To them, paradise is meeting Allah.
If we want to relate the relevant Qur'anic ayahs and the hadiths quoted from the infallible Ahlul Bayt, it would not be within the scope of these papers. Actually, even what has been said was out of the overflowing of the pen. Our major objective is to direct the attention of the hearts of the servants of Allah to what they have been created for, that is, to know Allah, which is superior to all sorts of happiness, and everything else is but a preliminary to it. By referring to "the thorns on the road of the suluk", we did not mean the great 'ulama of Islam, nor the honourable faqihs of the Ja'fari sect [may Allah's contentment be upon them], but we do mean some of the people of ignorance and those who pretend to be of the people of knowledge by means of insufficiency [qusur] and ignorance [jahl], not by means of negligence [taqsir] and abstinacy [`inad],and who became highway robbers of the servants of Allah. I take refuge with Allah from the evil of an overflowing pen, bad intention and false objective. Praise be to Allah at the beginning and the end, externally and internally.
. It means: "To be deluded by the appearance" or "To take an unreal matter for a real one".
. Furu'ul Kafi, vol. 3, p. 300, "Book of the Salat", ch. on "Submission in the Salat and Disapproving Toying", hadith 5.
. Ibid., hadith 4.
. `Ilalush-Shara'i` p. 88, as in Wasa'ilush-Shi`ah, vol. 4, p. 685, "Book of the Salat" chs. on "The Acts of the Salat" ch. 2, hadith 4.
. Falahus-Sail, p. 23. ch. 2, "On the Description of the Salat.
. Mustadrakul Wasa'il, "Book of the Salat", chs. on "The Acts of the Salat", ch. 2, hadith 3.
. Biharul Anwar, vol. 74, p. 74, "Book of Flower Garden", "The Prophet's Preachings", ch. 4, hadith 3. Makarimul Akhlaq, p. 459.
. Mustadrakul Wasa'il, "Book of the Salat", chs. on "The Acts of the Salat", ch. 1, hadith 7 , extracted from Fiqhur-Rida, p. 101, ch. on "The Obligatory salats".
. Surah Mud: 75.
. Mustadrakul Wasa'il, "Book of the Salat", chs. on "The Acts of the Salat" ch. 2, hadith 15.
. Surah at-Takathur: 8.
. Surah Ibrahim: 48.
. Surah Az-Zumar: 69.
. Surah an-Nur: 40.
source : Adabus Salat The Disciplines of the Prayer by Imam Khomeini