Chapter on the Virtue of Mosques and Prayer Within Them, and the Virtue of Congregational Prayer and Its Rulings

From him, from Yaqub ibn Yazid from Ibn Abi Umayr from Ibn Muskan from Abu Basir who said: I said to Abu Ja’far عليه السلام, peace be upon him: “(When praying) behind someone I do not follow in prayer, what should I do?” Imam عليه السلام said: “Finish (your recitation) before he finishes, for you are in confinement (hisar). If he finishes before you, then cut off your recitation and bow with him.”