O you who believe! Stand out firmly for justice, as witnesses to Allah, even as against yourselves, or your parents, or your family, and whether it is (against) rich or poor: for Allah can best protect both. Follow not the lusts (of your hearts), in case you swerve, and if you distort (justice) or decline to do justice, verily Allah is well- acquainted with all that you do. 4:135

Insult not to those whom they call upon besides Allah, in case they insult Allah in their ignorance. Thus have We made alluring to each people its own doings. In the end will they return to their Lord, and We shall then tell them the truth of all that they did. 6:108

As Prohet Muhammad Says " A muslim is one who's speech and hand others are safe. Sahi Buhkari

Say to My Follower that they should converse those things that are best: for Satan do spread conflict among them: For (Satan) is you open enemy. 17:53

O Mankind! We created you from a pair of a male and a female, and made you into nations and tribes, that you may identify each other. Verily the most honored of you in the sight of Allah is the most righteous of you. And Allah has full knowledge and is well acquainted (with all things). 49:13

As for those who divide their religion and break up into sects, you have no part in them in the least: their affair is with Allah. He will tell them of all that they did. 6:159