If One Prays Five Rak'ah Sunan Abi Dawud 1022
Translation
‘Abd Allah (b. Mas’ud) said; The Messenger of Allah (ﷺ) led us in five rak’ahs of prayer. When he turned away (i,e, finished his prayer), the people whispered among themselves. He asked; what is the matter with you ? They said
Abdullah reported: The Messenger of Allah (ﷺ) led us in prayer, praying five [rak'ahs]. When he turned away [from the prayer], the people whispered among themselves. He asked: "What is the matter with you?" They said: "O Messenger of Allah, has the prayer been increased?" He said: "No." They said: "Indeed, you have prayed five." So he turned away and prostrated two prostrations, then gave the salutation, and then said: "I am only a human being; I forget as you forget."