You who have been born again in Christ, listen to God speaking through me: “Sing to the Lord a new song” (Psalm 149:1). You say, “Well, I am singing!” Yes, you are singing but don’t let your life contradict your words. Sing with your voices, sing also with your hearts; sing with your mouths, sing also with your behavior. Do you want to sing God his praises? Be yourselves what you sing. You are his praise if you lead good lives.

—Augustine, Sermon 34.6