654 — Al-Hasan ibn al-Sabbāh related to me that he narrated from Abd al-Rahmān al-Muhāribī, from Abū Rajā, from Umar, the freedman of Ghufra, from Abd Allāh ibn Mamar, who said: Umar ibn al-Khattāb—may Allah be pleased with him—said: “Devote yourselves to the remembrance of Allah, for it is a cure; and beware of speaking about people, for it is a disease.”