Allah (SWT) the Exalted said in Noble Qur'an: "O' ye who believe! Avoid suspicion as much (as possible): for suspicion in s...
Allah (SWT) the Exalted said in Noble Qur'an: "O' ye who believe! Avoid suspicion as much (as possible): for suspicion in some cases is a sin: And spy not on each other behind their backs. Would any of you like to eat the flesh of his dead brother? Nay, ye would abhor it. But fear Allah: For Allah is Oft-Returning, Most Merciful." [Sura Hujurat 49:12]
Gossiping will also corrupt the tongue. The act of gossiping is bad since both the speaker and the listener are attacking a defenseless person. It is as if one eats the flesh of his dead defenseless brother and the other one attacks one who is not present there to defend himself. Four points are stressed in the Noble Qur'an in this regard:
(1) - Muslims and brothers in faith are just like our brothers.
(2) - A Muslim's honor is just like his flesh.
(3) - Gossiping behind his back to hurt his honor is like eating his flesh.
(4) - The fact that he is absent and is unable to defend himself is similar to him being dead. It is not right to attack a dead defenseless person.
That is why Imam Ali (as) has said: "Gossiping is done by weak people."
The second verse from Noble Qur'an regarding this issue is: "Those who love (to see) scandal published broadcast among the Believers, will have a grievous Penalty in this life and in the Hereafter: Allah knows, and ye know not." [Sura Al-Noor 24:19]
Man is a social creature and the society in which he lives is like his house. He should safeguard it just as he safeguards his house and prevent the influence of any corruption into the society. Islam seriously fights whatever corrupts the society. Gossiping is also seriously fought with because it unveils hidden flaws. Islam does not like this and instructs people to cover up each other's faults.
The third verse from Noble Qur'an regarding this issue is: "Allah loveth not that evil should be noised abroad in public speech, except where injustice hath been done; for Allah is He who heareth and knoweth all things." [Sura An-Nisa 4:148]
We must realize that any form of evil in public speech has been forbidden here. Thus gossiping is forbidden.
The fourth verse from Noble Qur'an in this regard is as follows: "Woe to every (kind of) scandal-monger and backbiter." [Sura Al-Humaza 104:1]
Some commentators have said that this verse was revealed about al-Walid ibn al-Mughirah who used to gossip behind Prophet Muhammad's (saw) back and made fun of him up front.