In the name of Allah, the Most Gracious, the Most Merciful.
Quran: Chapter 26 ‘Ha Meem’, Sura: 49 ‘Al Hujurat’ ‘The Dwellings’, Verse: 11
Verse 11: O you who believe! Let not a group scoff at another group; it may be that the latter are better than the former. Nor let (some) women scoff at other women, it may be that latter are better than the former. Nor defame one another, nor insult one another by nicknames. How bad is it to insult one’s brother after having faith [i.e. to call your Muslim brother (a faithful believer) as: “O sinner” or “O wicked”]. And who so ever does not repent then such are indeed, Zalimun, wrong doers.
Difficult words: Scoff: mock, ridicule, make fun of, laugh at, poke fun.
Notes by samia2010oct: It is Big Sin, Gunaah e Kabira, to scoff at your Muslim brothers in faith, to defame your Muslim brothers in faith, to insult your Muslim brothers in faith by calling them nicknames. For Big Sins there is the punishment of unbearable Blazing Hell Fire. It remains Big Sin when talked in these ways with in the family or about people out side one’s family, whether one knows other person thoroughly or not it remains a sin to talk in these ways. To talk in these ways is the sin of the tongue.