Abu Dardaa’ (radhiyalLaahu 'anh) narrates: The Messenger of Allaah (sallal Laahu 'alayhi wassallam) said: 

“Whoever protects the dignity of his brother, Allaah will protect his face against Hell on the day of Ressurrection.”

 - Tirmidhee #1931, Saheeh Targheeb #2848.