The Book of Psalms in the Septuagint (LXX), the ancient Greek translation of the Old Testament, has one more Psalm than does the Hebrew. It is said to be supenumerary. This note is usually appended to the song: "This Psalm is ascribed to David and is outside the number. When he slew Goliath in single combat." I set it to Genevan 78 because Psalm 78 is about David as shepherd, as is this song.