Quran 49:11 — The Walls (Al-Hujurat)

O you who believe, no people shall ridicule other people, for they may be better than they. Nor shall any women ridicule other women, for they may be better than they. Nor shall you mock one another, or make fun of your names. Evil indeed is the reversion to wickedness after attaining faith. Anyone who does not repent after this, these are the transgressors.

[49:10] The believers are members of one family; you shall keep the peace within your family and reverence GOD, that you may attain mercy.

[49:12] O you who believe, you shall avoid any suspicion, for even a little bit of suspicion is sinful. You shall not spy on one another, nor shall you backbite one another; this is as abominable as eating the flesh of your dead brother. You certainly abhor this. You shall observe GOD. GOD is Redeemer, Most Merciful.