Sunan an-Nasa'i 1244

Isma‘il ibn Mas‘ud reported to us; he said: Khalid ibn al-Harith reported to us, from Shu‘bah, who said: Mansur wrote to me. I read it back to him, and I heard him narrating to a man from Ibrahim, from ‘Alqamah, from ‘Abd Allah, that the Messenger of Allah (ﷺ) prayed the Zuhr prayer, then turned to face them. They said: “Has something happened in the prayer?” He said: “What is that?” They told him what he had done. He folded his leg, turned toward the qiblah, and prostrated twice. Then he said the taslim, turned to face them, and said: “I am only a human being; I forget just as you forget, so remind me when I forget.” He also said: “If something had happened in the prayer, I would have informed you.” And he said: “If any one of you becomes uncertain during his prayer, let him determine which course is closest to what is correct, complete the prayer on that basis, and then prostrate twice.”