49:13 O mankind! We created you from a single (pair) of a male and a female and made you into nations and tribes that ye may know each other (not that ye may despise each other). Verily the most honored of you in the sight of Allah is (he who is) the most righteous of you. And Allah has full knowledge and is well acquainted (with all things).
He who accuses another Muslim of a sin for which he has already repented, then the accuser will not die until he has committed that sin himself. (Tirmizi)