Musannaf Ibn Abi Shaybah 32465 — Book of Faith

Adi bin Adi (may Allah have mercy on him) said that Umar bin Abd al-Aziz (may Allah have mercy on him) wrote to me, saying: "After praise and salutations: Indeed, faith has certain obligations, commands, limits and regulations. Whoever fulfils them has completed his faith, and whoever does not fulfil them has not completed his faith. If I live, I will soon explain them to you so that you may act upon them, and if I die before explaining this, I am not very eager for your company."