Messiaen Vingt Regarde #1 Actually sounds pretty religious.
Messiaen is about as religious as Christopher Hitchens after downing a crate of scotch.
Second movement (Andante) of Schubert Sonata #6 D.V. 664, Op. 120. Adequately religious sounding while also musically rewarding to play. Oh, and while we're at it, your father's concept of "sharing your talents with the world" is in desperate need of revision.