Chapter on the Rulings of Congregational Prayer (the Minimum Number for Congregational Prayer, the Description of the Imam, Who Is to Be Followed and Who Is Not to Be Followed, Recitation Behind Both of Them, the Rulings of Those Led in Prayer, and Other Such Rulings Related to It)

Muhammad ibn Yaqub narrated from Muhammad ibn Ismail, from al-Fadl ibn Shadhan, and from Ali ibn Ibrahim, from his father, both from Hammad, from Hariz, from Zurarah, who said: I said to Abu Ja’far عليه السلام, peace be upon him: “A man entered with a group in their prayer while he did not intend it as prayer, then their imam (of prayer) became invalidated (entered a state of hadath), so the imam (of prayer) took the hand of that man and placed him forward, and he led them in prayer. Does their prayer count when he was leading them without having intended it as prayer?” Imam عليه السلام said: “It is not appropriate for a man to enter with a group in their prayer while he does not intend it as prayer. Rather, he should intend it as prayer. So if he had already prayed, then for him it will count as another prayer, and if not, then he should not enter with them. As for the group, their prayer may be valid even if he had not intended it.”