Sunan an-Nasa'i 1260

Al-Rabi‘ ibn Sulayman reported to us; he said: Shu‘ayb ibn al-Layth reported to us; he said: al-Layth reported to us, from Muhammad ibn ‘Ajlan, from Muhammad ibn Yusuf, the freedman of ‘Uthman, from his father Yusuf, that Mu‘awiyah led them in prayer. He stood at a point during the prayer when he should have sat. The people said tasbih, but he continued standing. Then, after completing the prayer, he prostrated twice while seated. He then sat on the minbar and said: I heard the Messenger of Allah (ﷺ) say: “Whoever forgets something in his prayer, let him prostrate twice like these two prostrations.”