Prohibition of Calumny

Allah, the Exalted, says:

"A slanderer, going about with calumnies." (68:11)

"Not a word does he (or she) utter, but there is a watcher by him ready (to record it)." (50:18)

Hudhaifah (RA) said: The Messenger of Allah (PBUH) said, "The person who goes about with calumnies will never enter Jannah." 
[Al-Bukhari and Muslim]

Ibn 'Abbas (RA) said: The Messenger of Allah (PBUH) passed by two graves and said, "Both of them (the persons in these graves) are being tortured, and they are not being tortured for a cardinal sin. But indeed they are great sins. One of them used not to save himself from being soiled with his urine, and the other one used to go about with calumnies (among the people to rouse hostilities, e.g., one goes to a person and tells him that so-and-so says about him such and such evil things)." 
[Al-Bukhari and Muslim]

Ibn Mas'ud (RA) said: The Prophet (PBUH) said, "Shall I tell you what 'Al-'Adhu' (falsehood and slandering) is? It is calumny which is committed among the people." 
[Al-Bukhari and Muslim]

Commentary

As observed from above ayahs and ahadith calumny or tale bearing is prohibited in Islam. The punishment of such slanderous act is hell. Person, who practices calumny with the intention to create conflict and quarrel among people although knowing that it is unanimously forbidden, will never enter Janna. Same is the fate for a person who does it out of sheer human weakness, but if Allah forgives him he might be pardoned. The second hadith infers that calumny is a not a cardinal sin therefore the punishment related to it won’t be plain as well. The momentous retribution for this kind of sin is harsh punishment in grave.  Another sin pointed in the hadith is not passing urine in privacy but doing it shamelessly in the presence of other people. From the third hadith we learn that calumny, lying, falsehood and slandering are major sins because they cause clash and discord in society. A Muslim must keep himself free from such evils.