Ibn al-Qayyim (رحمه الله) said:[1]
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Beware of lying for it corrupts your (proper) conception (taṣawwur) of the knowledge (of things) as they really are, and it spoils your comprehension of them and teaching them to people. For the liar portrays the non-existent as existent and the existent as non-existent, the truth as falsehood and falsehood as truth, thus corrupting his conception and knowledge, [this being] a punishment for him.
Then he portrays (this erroneous conception) to the soul of the one who is deceived by him and inclined towards him, thereby corrupting his conception and knowledge. The soul of the liar is turned away from the existent reality, and inclined to nothingness, giving preference to falsehood.
When the strength of his conception and knowledge is corrupted, (a strength) which is the origin of every chosen action, those actions are also corrupted, and the judgement of lying is applied to them. So the occurrence of these actions from him is like the occurrence of lying on his tongue, hence, he does not benefit from his tongue or his actions.
For this reason, lying is the basis of sinfulness (fujūr), as the Prophet (صلى الله عليه وسلم) said: “Lying leads to sinfulness, and sinfulness leads to Hellfire.”[2] The first thing that lying spreads to from the soul is the tongue, corrupting it, then it spreads to the limbs and corrupts its actions just as it corrupted the tongue's statements.
Thus, lying spreads to all of his words, deeds and states, and then corruption takes hold of him, and then its disease (grows) and leads him to destruction, if Allāh does not save him with the medicine of truthfulness, to uproot (lying) from its foundation. For this reason, the origin of the actions of the heart is truthfulness, and its opposites—such as showing off, arrogance, pride, vanity, conceit, incapacity, laziness, cowardice, humiliation and others—have their origin in lying.
Thus, every righteous deed, apparent or hidden, its origin is from truthfulness, and every corrupt deed, whether apparent or hidden, its origin is from lying.
Lying emanates from the heart and then spreads to the tongue and then also to actions. Hence, lying is not only in speech, rather, a person can also lie in his actions, wherein his actions and behaviours are contrary to the reality, being a lie, even if to the onlooker, they appear otherwise.
This is because the tongue is the transcript of the heart, just as we say in the subject of īmān, that the belief of the heart is its speech. So speech is a transcription of the heart, and the actions are a transcription likewise. So lying occurs in both speech and in action, not just in speech alone. The one who lies is punished for his lying in this manner, until the affair overwhelms him, and he becomes a lie himself.
Thus, the people are of two types, those who are people of truthfulness, and those who are people of lying and lying draws a person towards hypocrisy, because lying is one of its chief characteristics. Hence, you will see in the liars, contradictory, conflicting, incoherent words and deeds, that can’t be reconciled with each other, we ask Allāh for safety.
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