Allah Most High states, {Then let us earnestly pray and invoke the curse of Allah on those who lie!} (Al-'Imran: 61)

{Allah guides not one who transgresses and lies!} (Ghafir: 28)

{Cursed be the conjecturers (the liars).} (Al-Dhariyat: 10)

On the authority of Ibn Mas'ud (may Allah be pleased with him), "the Messenger of Allah (pbuh)

said, "Adhere firmly to truthfulness for truthfulness surely leads to righteousness and righteousness leads to Paradise, and a man is recorded with Allah as a sincere one as long as he is truthful.

However, lying leads to immorality and immorality leads to the Hell-Fire, and a man is recorded with Allah as a liar as long as he lies.”1

He (pbuh) also said, "Three are the signs of the hypocrite, even if he prays, fasts, and pretends to be a Muslim: When he talks, he lies; when he makes a promise he breaks it; and when he is given a trust, he betrays it” 2

In another narration it is reported on the authority of ' Abdullah Ibn 'Vmar that the Prophet (pbuh) said, "Four traits if found together in a person make him a hypocrite. Whoever has one of these, possesses one of the hypocritical characteristics until he renounces it: When he speaks, he lies; when he draws a contract, he breaches it, When he makes a promise, he breaks it; and he abuses his opponents in time of dispute.” 3

AI-Bukhari reported in his Sahih the following hadith on the authority of Samarah Ibn Jundub (may Allah be pleased with him):

"The Messenger of Allah (pbuh) used to ask, "Did anyone of you see a dream?" So those whom Allah wished to tell would narrate dreams to him. One morning the Prophet (pbuh) said, "Last night two persons came to me in a dream and woke me up and said to me, 'Proceed!' I set out with them... And we came to a man laying flat on his back and another man standing over his head with an iron hook, and behold, he would put the hook in one side of man's mouth and tear off that side of his face to the back of the neck and similarly tear his nose from front to back and his eyes from front to back. Then he turned to the other side of the man's face and did just as he had done with the other side. He hardly completed this side when the other side returned to its normal state. Then he returned to repeat what he had done before. I said to my two companions, 'Glory be to Allah! Who are these two persons?'... They said, 'This man is the symbol of the person who goes out of his house in the morning and tells so many lies that it spreads all over the world. '" Allah's Messenger (pbuh) also said, "The believer may be naturally disposed to any shortcoming except treachery and lying.” 1

Other hadith states, "Beware of suspicion for suspicion is the most untruthful of speech.”2

"There are Three types of people with whom Allah would neither speak to on the Day of Judgment, nor would He look towards them, nor would He purify them (from sins) and there would be a tormenting chastisement for them: The aged adulterer, the lying ruler and the destitute who is full of pride.”3

"Woe to the one who tells lies to make people laugh. Woe to him, woe to him.”4

False oaths are more heinous than the normal lying. Allah says about the character of the hypocrites:

{And they swear to falsehood knowingly.} (AI-Mujadilah: 14)

Furthermore, the Messenger of Allah (pbuh) said, "There are three people whom Allah will not speak to, look at, or exonerate on the Day of Judgment, and who will have a painful torment: he who withholds what he has of excessive water from a traveler in the desert, he who sells merchandise after Asr (Late Afternoon) swearing by Allah that he paid more for it than he actually did, and a man gives the pledge to a governor only for the sake of this world,' he will only be loyal if he gets something of this worldly life.” 5

The Messenger of Allah (pbuh) said, "!t is a grievous treachery to tell your brother lies when he believes what you say.” 6

A Hadith states, "Whoever claimed to have seen a vision while he is lying, on the Day of Judgment he will be commanded to tide two hairs which is impossible.”7

The Messenger of Allah (pbuh) said, "The worst sin in the sight of Allah is the false witness.”1

Ibn Mas'ud (may Allah be pleased with him) said, "A servant insists on lying until a black dot be stamped over his heart and so his heart would be stamped as a whole with black color. With Allah such servant would be recorded as a liar.”2

The Muslim, therefore, is required to utter only the good words to be safe from error. Al-Bukhari reported on the authority of Abu Huriarah (may Allah be pleased with him) that the Messenger of Allah (pbuh) said, "Whoever believes in Allah and in the Last Day should utter only good word or he should keep silent." This agreed upon hadith indicates clearly that a person should not speak except with what seems to him as good.

Abu Musa (may Allah be pleased with him) said that, "I asked the Messenger of Allah, '0 Messenger of Allah! Who amongst Muslims is the most charitable?' He (pbuh) responded, "The one who from his tongue and hands Muslims are safe.”3

It is reported in the two Sahihs that, "A servant may utter a word while he is unaware of its consequences, by it he would be thrown in Hell for a distance more far than the distance between the east and west.” Bilal Ibn Al-Harith Al-Muzani said the Messenger of Allah (peace be upon him) declared, "A man may speak a word out of Allah's Pleasure while he is unaware of its fruits, by which Allah decree pleasure for that man until he meets Him. On the other hand, a man may speak a word out of Allah's wrath while he is unaware of its consequences, by which Allah decree for him displeasure until he meets Him. " Once a righteous man was questioned about the number of Man's faults. Thereupon, he answered, "Man's faults are innumerable but I know 8000 faults. However, man can conceal these numerous faults through keeping silent with the exception of good speak.