Sahih Muslim Book 32, Hadith Number 6267.

Chapter : Tidings for one whose faults Allah concealed in this world: He will also conceal his faults in the hereafter.

Abu Huraira reported Allah’s Apostle (may peace be upon him) as saying: The servant (who conceals) the faults of others in this world, Allah would conceal his faults on the Day of Resurrection.