It is narrated from Sayyiduna Shihab (may Allah be pleased with him), who was one of the Companions of the Messenger of Allah (peace and blessings be upon him) and resided in Egypt, that he heard the Messenger of Allah (peace and blessings be upon him) say: "Whoever conceals a fault of a believer, it is as though he has brought a dead person back to life."
Hadith Referenceالمعجم الكبير للطبراني / باب الشين / 7200