The Quran 49:11 (Surah al-Hujurat)
Complete Verse 49:11 (Translated by Muhsin Khan)
“O ye who believe!
Do not ridicule others, perhaps they may be better than you.
And do not insult one another, nor call each other by offensive names.
Lewdness is surely ill-seeming, and those who do not desist are indeed wrongdoers.”