Chapter on the Rulings on Forgetfulness (Ahkam al-Sahw)

From him, from Faddalah, from al-Husayn ibn ‘Uthman, from Sama‘ah, from Abu Basir, who said: I asked Abu Abdillah عليه السلام, peace be upon him, about a man who prayed two rak‘ahs and then got up and went about his need. Imam عليه السلام said: "He must begin the prayer anew." I asked: “Why is it that the Messenger of Allah سبحانه وتعالى, peace be upon him and his family, did not restart the prayer when He صلى الله عليه وعلى آله وسلم had prayed two rak‘ahs?” Imam عليه السلام said: "The Messenger of Allah سبحانه وتعالى, peace be upon him and his family, had not left his place."