Sahih Bukhari Volume 008, Book 078, Hadith Number 660.

Narated By Abu Huraira : A man entered the mosque and started praying while Allah's Apostle was sitting somewhere in the mosque. Then (after finishing the prayer) the man came to the Prophet and greeted him. The Prophet said to him, "Go back and pray, for you have not prayed. The man went back, and having prayed, he came and greeted the Prophet. The Prophet after returning his greetings said, "Go back and pray, for you did not pray." On the third time the man said, "(O Allah's Apostle!) teach me (how to pray)." The Prophet said, "When you get up for the prayer, perform the ablution properly and then face the Qibla and say Takbir (Allahu Akbar), and then recite of what you know of the Quran, and then bow, and remain in this state till you feel at rest in bowing, and then raise your head and stand straight; and then prostrate till you feel at rest in prostration, and then sit up till you feel at rest while sitting; and then prostrate again till you feel at rest in prostration; and then get up and stand straight, and do all this in all your prayers."