I'm surprised nobody mentioned Handel's Messiah. The Hallelujah chorus is, in my opinion, one of the best practical illustrations of the theme of the above article.

The traditional Catholic hymn Te Deum sounds beautifully solemn when sung as an a cappella Gregorian chant, but when done in an arrangement for chorus and organ, it is, for me at least, mind-blowing. (Of course, a Youtube recording doesn't come close to the experience of hearing it live in a church with a large organ.)

As for the Russian Orthodox music, this rendering of Grechaninov's Credo is one of my favorite vocal performances I've ever heard.