Question
Why do we sway when we pray?
Answer
The Talmud Bavli (Berachos 28b) says that when a person prays, he must bow until all the segments of his spine are separated; the Talmud Yerushalmi says that a person who stands and prays should bow at every prayer, based on the verse (Psalms 35:10) “All my bones will say ‘Ha-Shem, who is like You?’”