The Latin phrase "Soli Deo Gloria" is familiar to all church musicians. Bach famously wrote it on his manuscripts, and many composers since then have picked up on the habit. The picture with this post is from Handel, and you can see it has been shortened to SDG. It can be translated as "To God alone be the glory."
This Sunday the Wittenberg Choir will be visiting, and they will be fully incorporated into the structure of a worship service that still includes readings and prayers and communion. Maintaining the liturgical structure allows us to remember that the beautiful music is not an end in itself, but a symbol, a guidepost pointing in the proper direction. The only difference between a hymn and an anthem, or between the prelude and the liturgy is the people who are participating directly in the music. In all cases, the music is to the glory and praise of God. Soli Deo Gloria.