يٰٓاَيُّهَا الَّذِيْنَ اٰمَنُوْا لَا يَسْخَرْ قَوْمٌ مِّنْ قَوْمٍ عَسٰٓى اَنْ يَّكُوْنُوْا خَيْرًا مِّنْهُمْ وَلَا نِسَاۤءٌ مِّنْ نِّسَاۤءٍ عَسٰٓى اَنْ يَّكُنَّ خَيْرًا مِّنْهُنَّۚ وَلَا تَلْمِزُوْٓا اَنْفُسَكُمْ وَلَا تَنَابَزُوْا بِالْاَلْقَابِۗ بِئْسَ الِاسْمُ الْفُسُوْقُ بَعْدَ الْاِيْمَانِۚ وَمَنْ لَّمْ يَتُبْ فَاُولٰۤىِٕكَ هُمُ الظّٰلِمُوْنَ ( الحجرات: ١١ )
Yaaa ayyuhal lazeena aamanoo laa yaskhar qawmum min qawmin 'asaaa anyyakoonoo khairam minhum wa laa nisaaa'um min nisaaa'in 'Asaaa ay yakunna khairam minhunna wa laa talmizooo bil alqaab; bi'sal ismul fusooqu ba'dal eemaan; wa mal-lam yatub fa-ulaaa'ika humuz zaalimoon (al-Ḥujurāt 49:11)
O you who have believed, let not a people ridicule [another] people; perhaps they may be better than them; nor let women ridicule [other] women; perhaps they may be better than them. And do not insult one another and do not call each other by [offensive] nicknames. Wretched is the name [i.e., mention] of disobedience after [one's] faith. And whoever does not repent – then it is those who are the wrongdoers. (Al-Hujurat  : 11)
1 Mufti Taqi Usmani
O you who believe, no men should ever scoff at other men. May be, the latter are better than the former. Nor should women (ever scoff) at other women. May be, the latter women are better than the former ones. And do not find fault with one another, nor call one another with bad nicknames. Bad is the name of sinfulness after embracing Faith. If anyone does not repent, then such people are the wrongdoers.