Musnad Ahmad 724:6

Yahya ibn Sa’id narrated to us, Ibn ‘Ajlan narrated to us, ‘Ali ibn Yahya ibn Khallad narrated to us, from his father, from his uncle—and he was a Badrī (a veteran of Badr)—who said: We were with the Messenger of Allah, peace and blessings of Allah be upon him, in the mosque, when a man entered and prayed in a corner of the mosque. The Messenger of Allah, peace and blessings of Allah be upon him, began to watch him. Then he came and greeted him, so he returned the greeting to him and said: "Go back and pray, for you have not prayed." So he went back and prayed, then he came and greeted him, so he returned the greeting to him and said: "Go back and pray, for you have not prayed." He said this two or three times. Then he said to him on the third or fourth time: "By the One who sent you with the truth, I have exhausted myself, so teach me and show me." The Prophet, peace and blessings of Allah be upon him, said to him: "When you intend to pray, perform wudu (ablution) and perfect your wudu, then face the Qiblah, then say the Takbir, then recite, then bow until you are at ease while bowing, then rise until you are at ease while standing, then prostrate until you are at ease while prostrating, then rise until you are at ease while sitting, then prostrate until you are at ease while prostrating, then stand up. If you complete your prayer in this manner, then you have completed it; and whatever you diminish from this, you are only diminishing it from your prayer."