Sunan Ibn Majah, Chapter: The Chapters of Establishing the Prayer and the Sunnah Regarding Them

"I asked Aishah: 'How did the Messenger of Allah (saw) perform prayer?' She said: 'When the Prophet (saw) performed ablution, he would put his hand in the vessel and say Bismillah, and he would perform ablution properly. Then he would stand and face the Qiblah. He would say the Takbir raising his hands parallel to his shoulders. Then he would bow, putting his hands on his knees and keeping his arms away from his sides. Then he would raise his head and straighten his back, and he would stand a little longer than your standing. Then he would prostrate, pointing his hands towards the Qiblah, keeping his arms away (from his sides) as much as possible, according to what I have seen. Then he would raise his head and sit on his left foot with his right foot held upright, and he disliked leaning towards his left side.'" Sahih