Q. Why do we kneel on Yom Kippur?
A. Kneeling was common in Biblical times and it played a dramatic role in the Temple on Yom Kippur when the kohanim and the people heard the name of God. We colourfully re-enact the account of the Temple ritual, accompanied by our kneeling and prostrating ourselves.
In many congregations we also kneel during Musaf on Rosh HaShanah and Yom Kippur when Alenu is recited; by kneeling we are defiantly proclaiming, “No-one will prevent us from acclaiming the true God”.
In many places paper is placed on the floor before worshippers kneel in order to avert any suspicion that we are bowing down to stone (Lev. 26:1).