Muhammad ibn Ahmad ibn Yahya from Al-Hasan ibn Ali ibn Abdillah from Ibn Faddal from Marwan from ‘Ammar al-Sabati, who said: We were sitting with Abu Abdillah عليه السلام at Mina when a man said to him: “What do you say about the nawafil (supererogatory prayers)?” Imam عليه السلام said: “They are obligatory (faridah).” We were alarmed, and the man was alarmed too. Then Abu Abdillah عليه السلام said: “I only mean the night prayer upon the Messenger of Allah سبحانه وتعالى, may Allah سبحانه وتعالى bless him and his family. Indeed, Allah سبحانه وتعالى says: ‘And in the night, keep vigil with it as a supererogatory act for you’” (Surah Al-Isra’ 17:79).