Chapter on the Manner of Prayer, Explanation of the Fifty-One Rak‘ahs; The Order, Recitation, Tasbih in Bowing and Prostration, Qunut, and What is Obligatory and Recommended Therein

Muhammad ibn al-Hasan ibn al-Walid narrated from al-Saffar from Muhammad ibn Isa from Hafs al-Jawhari, who said: Abu al-Hasan Ali ibn Muhammad عليه السلام, peace be upon him, led us in the Maghrib prayer, then He عليه السلام performed the prostration of gratitude after the seventh (rak‘ah). So I (narrator) said to Him عليه السلام: “Your forefathers عليه السلام used to perform the prostration after the third (rak‘ah).” Imam عليه السلام said: “None of my forefathers عليه السلام performed the prostration except after the seventh.”