Sung congregational worship is a part of a broader Word ministry.
Rob Smith recently put it like this:
As well as being a form of praise and a form of prayer, singing is also a form of proclamation. For the Scriptures reveal that the life-giving word of God is ministered among the people of God not only by Bible reading and biblical preaching, but also by the singing of “psalms, hymns and spiritual songs” (Col 3:16).
Rob points out, importantly:
Evidently, this does not mean that the sung word is meant to eclipse the spoken word, or that singing should replace the public reading of Scripture and preaching and teaching (1 Tim 4:13). Neither Jesus nor the apostles preached the gospel by singing it! Therefore, the sung word is not to rival the spoken word in the church’s preaching ministry, but is designed to function as its handmaid and complement.
If our songs are soaked with the text and themes of the Bible (and they should be), then it our songs should have the same kind of focus, or trajectory as the Bible, and our preaching of it. That focus, and trajectory is the central figure in God’s great redemptive narrative: Jesus, who is not only creator, but will establish the new creation. It is Jesus himself who tells us that the scriptures are all about him (Luke 24). In fact, we see this tragectory so clearly in John’s great revelation. We see Jesus, the Lord of all history being worshiped, and his great redeeming sacrifice being retold:
And they sang a new song, saying,
“Worthy are you to take the scroll
and to open its seals, for you were slain,
and by your blood you ransomed people for God
from every tribe and language and people and nation,
and you have made them a kingdom and priests to our God, and they shall reign on the earth.”
(Revelation 5:9-10 ESV)
The worship of heaven in focussed on Jesus and what he did. Our earthly worship is a foretaste of this. When our songs are full of scripture, they are full of Jesus, his cross and resurrection, for that is the climax of scripture and of redemptive, indeed, human history.