Sunan an Nasa’i: 13 The Book of Forgetfulness (In Prayer)
Ali bin Yahya bin Khallad bin Raf' bin Malik Al-Ansari said:
"My father narrated to me that a paternal uncle of his, who had been at Badr, said: 'I was sitting with the Messenger of Allah (ﷺ) in the masjid when a man came in and prayed two rak'ahs, then he came and greeted the Prophet (ﷺ) with salam. The Prophet (ﷺ) had been watching him as he prayed, so he returned his salam, then he said: "Go back and pray, for you have not prayed." So he went back and prayed, then he came back and greeted the Prophet (ﷺ) with salam. He returned the salam, then he said: "Go back and pray, for you have not prayed." The third or fourth time this happened, then the man said: "By the One Who revealed the Book to you, I have done my best and have tried hard; show me and teach me." He said: 'When you want to pray, perform wudu and do it well, then turn to face the Qiblah and say the takbir. Then recite the Quran, then bow until you are at ease in bowing. Then stand up until you are standing straight, then prostrate until you are at ease prostrating, then sit up until you are at ease sitting, then prostrate until you are at ease prostrating, then get up. If you complete the prayer in this manner you wil hve done it properly, and whatever you do less than this is lacking from you prayer.'"
Sunan an Nasa’i: 13 The Book of Forgetfulness (In Prayer) 1315