We take worship in song seriously. Singing is not the only act of worship, but the bones of praise move best with the muscles of melody held in by the skin of songs.
What happens when we learn and sing good songs of worship? The body is encouraged, yes. But the body is also made more accountable.
In Deuteronomy 31 the Lord told Moses that his days of leading Israel were almost finished. The remaining task the Lord gave to Moses was to “write this song and teach it to the people of Israel. Put it in their mouths….” The “Song of Moses” takes up 43 verses in chapter 32 and is harmonized in Revelation 15:3 with “the song of the Lamb”: “Great and amazing are your deeds, O Lord God the Almighty! Just and true are your ways, O King of the nations!”
But as it provided an outlet for expressing thanks and adoration, the song also provided accountability. “Put [this song] in their mouths, that this song may be a witness for me against the people of Israel” (verse 19). The Lord knew that after the many blessings He would give that they would have “eaten and are full and grown fat, they will turn to other gods and serve them, and despise me” (verse 20).
when many evils and troubles have come upon them, this song shall confront them as a witness (for it will live unforgotten in the mouths of their offspring). (verse 21)
Much is required of those to whom much is given. We have been given the privilege of many psalms and hymns and spiritual songs, and they call us to account for whether we are fearing the Lord and glorifying His name.