Sahih Muslim
The Book of Prayers (Kitab Al-Salat)
Book Number: 004 / Hadith Number: 792
Wa'il b. Hujr reported: He saw the Apostle of Allah (may peace be upon him) raising his hands at the time of beginning the prayer and reciting takbir, and according to Hammam (the narrator), the hands were lifted opposite to ears. He (the Holy Prophet) then wrapped his hands in his cloth and placed his right hand over his left hand. And when he was about to bow down, he brought out his hands from the cloth, and then lifted them, and then recited takbir and bowed down, and when (he came back to the erect position) he recited:" Allah listened to him who praised Him." And when prostrates. he prostrated between the two palms.