Folks, if we're going to talk about composers who were not religious and put it in their works, look no further than Scott Joplin. In his 1915 opera, Treemonisha, he equates hoodoo and Christianity both as rank superstition holding black people back. In the clip below, we see Parson Alltalk sermonizing while the "conjurors" walk among the crowd throwing magic dust. Joplin told them through the main character that the true way to liberation was through education not religion.

In the clip, the people are told to be good not because a god cares or because the bible says so but merely because it is:

Good Advice