The use of song as a vehicle for conveying the Word of God has biblical precedent. It comes from a vignette near the end of the Israelite wandering in the wilderness. Moses and Joshua were summoned to the Tent of Meeting to receive final instructions from God before Moses was to relinquish leadership prior to the Israelite entry into Canaan.

On this occasion there was a preface to the instruction that was to be relayed to the people: “Write this song, and teach it to the Israelites; put it in their mouths, in order that the song may be a witness for me” (Deut. 31:19).

In the first 43 verses of the following chapter is recorded the revelation that was provided–in song–for God’s people at that strategic time in their pilgrimage. (Perhaps this is the origin of the term “message in song,” which is used in some church bulletins…)

from Dialogue of Worship