J. S. Bach's B Minor Mass. Who says Lutherans can't write good church music?
Bach is my favourite too. Together with Handel.
Have you listened to Bach's passacaglia and fugue in C minor for organ? That's one of my favourites among all the other wonderful compositions of his.
Bach was a very pious Christian and very modest, far from vainglory. He said that if music is not written to God's glory, then it's nothing but satanic creak. This means, he himself composed only to God's glory. He would write the letters SDG on the sheets of his music, that is, Soli Deus Gloria = Glory to God only.