I saw `Abdullah bin `Umar crossing his legs while sitting in the prayer and I, a mere youngster in those days, did the same. Ibn `Umar forbade me to do so, and said, "The proper way is to keep the right foot propped up and bend the left in the prayer." I said questioningly, "But you are doing so (crossing the legs)." He said, "My feet cannot bear my weight."
Sahih al-Bukhari Book 10, Hadith 221
← Previous Hadith `Imran and I prayed behind `Ali bin Abi Talib and he said Takbir on prostrating, on rising and on getting up after the two rak`at (i.e. after the second rak`a). When the prayer was finished, `Imran took me by the hand and said, "He (`Ali) has prayed the prayer of Muhammad" (or said, "He made us remember the prayer of Muhammad).

Sahih al-Bukhari Book 10, Hadith 220 Next Hadith → I was sitting with some of the companions of Allah's Messenger (ﷺ) and we were discussing about the way of praying of the Prophet. Abu Humaid As-Sa`idi said, "I remember the prayer of Allah's Messenger (ﷺ) better than any one of you. I saw him raising both his hands up to the level of the shoulders on saying the Takbir; and on bowing he placed his hands on both knees and bent his back straight, then he stood up straight from bowing till all the vertebrate took their normal positions. In prostrations, he placed both his hands on the ground with the forearms away from the ground and away from his body, and his toes were facing the Qibla. On sitting In the second rak`a he sat on his left foot and propped up the right one; and in the last rak`a he pushed his left foot forward and kept the other foot propped up and sat over the buttocks."

Sahih al-Bukhari Book 10, Hadith 222