There are as many advantages for truthfulness as there are disadvantages for lying. Truthfulness is one of the most beautiful traits and lying one of the ugliest. The tongue translates man's internal feelings to the outside, therefore if lying stems from envy and or enmity it is one of the dangerous signs of anger; and if it stems from stinginess or habit, it is from the effects of the burning lusts of man.
If man's tongue becomes poisoned with lying an its filth appears on him, its effects are like the effects of the autumn wind on the leaves of trees. Lying extinguishes the light of man's existence and lights the fire of treachery in him. It also has an amazing effect in terminating the ties of unity and harmony between men and spreads hypocrisy. As a matter of fact, a great deal of misguidance springs from false claims and empty words. For men with evil intentions, lying is an open door to help them reach their selfish goals by concealing the facts behind their magical words and capturing innocent people with their poisonous lies.
Liars leave no time for themselves to think or reflect. They rarely think about the possible conclusions, claiming that "no one will ever discover their secrets." In their words we find many mistakes and contradictions, liars will eternally become covered with shame, failure and disgrace. It is true, therefore, to say that "liars have bad memories".
One of the factors which spreads this resentful trait which poisons social manners is the saying:
"Constructive lying is better than the painful truth."
This saying has become a veil to cover this lonely trait, and many people resort to it in order to justify their resentful lies. These people ignore what reason and jurisprudence say about this issue. Islam and reason command that if a Muslim's soul, honor or essential belongings are endangered it is his obligation to defend them by any means possible, including lying. It is a valid maxim that say, "necessities legalize the prohibited". Necessary lying has its limitations, it must stop on the border of necessity. If men widen the circle of "constructiveness" to include their personal wishes and lusts, there would not be a lie without a so-called need behind it. One of the great scholars says in this regard:
"There is a reason for everything. It is possible for us to invent factors and reasons for all actions. Even the professional criminals have excuses for their crimes. Therefore, there are advantages and needs for every lie ever uttered. In other words, every lie that is told serves a purpose and the liar is good: if a liar gained nothing from lying there would be no reason to hide the facts. This stems from the fact that it is man's nature to consider everything that may be advantageous to him to be good. If man suspects that his personal benefits may be endangered by the truth, or imagines there is goodness in lying, then he lies without any hesitation for he see evil in the truth and goodness in lying."
We should not ignore the fact that lying is a great evil, and that if some harm is removed by lying (when permitted), it is with the view of countering the greater evil with a lesser one.
The freedom of speech is more important than the freedom of thinking because if someone makes a mistake when exercising his freedom to think, only that individual is harmed. One the other hand, when exercising the freedom of speech, the welfare of the society is at stake. The advantages and disadvantages of freedom of speech affect the whole society.
Ghazali has said:
"The tongue is a beneficial gift. It is a delicate creature, which regardless of its small size performs an extremely important job when it comes to obedience an disobedience. Both disbelief and faith are manifested with the tongue, and they are the ultimate worship or disobedience."
He then added:
"Only those who can confine their tongues to religion are able to avoid evil. These people never set their tongues free unless it is beneficial to their lives, faith, and eternal place of rest."
Abu Hamid al-Ghazali, Kimiyaye Sa'adat
It is important to avoid lying and contradicting the truth in front of children so that this evil trait does not enter their hearts. Children learn how to act and speak from their families and those around them.
Therefore, if lying and/or contradicting the truth penetrates the family atmosphere, children will be affected and in turn be inflicted with the same illnesses.
Morris T. Yash said:
"The habit of thinking, speaking, and endeavoring to find the facts is only practiced by those who were brought up surrounded by it as children."
source : Title: Youth and Morals Author: Sayyid Mujtaba Musavi Lari