1. Do you mean that the words of the song are the words from specific religious texts? If so, then one way to say it would be "This song is a piece of scripture set to music." 2. The same could be said for this one. "This song is a Chinese poem set to music."

1. I guess for the first one, you could say “this song was inspired by scripture” or if you are talking to someone as big dumb as me, replace scripture with “religious text” or “the Bible. 2. You could say “this song was made using chinese poetry” or “this song was inspired by chinese poetry” it really depends on if there are direct quotes or not