Never Insult others
Narrated Abdullah bin Amr: Allah’s Apostle neither talked in an insulting manner nor did he ever speak evil intentionally. He used to say, “The most beloved to me amongst you is the one who has the best character and manners.” He added, “Learn the Qur’an from (any of these) four persons: ‘Abdullah bin Mas’ud, Salim the freed slave of Abu Hudhaifa, Ubai bin Ka’b, and Mu’adh bin Jabal.”
Sahih Al-Bukhari – Book 57 Hadith 104
