Abd al-Jabbar bin Wa'il (may Allah have mercy on him) narrates, through some people of his family, from his father that he saw the Prophet (peace and blessings be upon him): when he (peace and blessings be upon him) began the prayer he would raise his hands, place the right hand on the left, and hold his palms.
Hadith Referenceالمعجم الكبير للطبراني / باب الواو / 18296