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

And from him, from Ali, from his father, from Hammad, from Hariz, from Abu Basir: Abu Abdillah عليه السلام said: “Any man who leads a group (in prayer) is required to remain seated after the taslim and not leave that spot until those behind him who had missed part of their prayer have completed it. This is obligatory upon every imam (of prayer) when he knows that among them is someone who has missed part of the prayer. But if he knows that there is no one among them who has missed part of the prayer, then he may go wherever he wishes.”