I will sing of steadfast love and justice;
to you, O Lord, I will make music.
David's heart for worship shows in this passionate purpose statement. David is determined to be a man of praise. He has seen both God's grace and God's justice in the life of Israel and that is why he wants to sing to the Lord.
A heart of praise flows from our relationship with God. If we love God, we should want to praise Him with His people. And not just musicians should desire this. The call to praise came from an awareness of God's justice and God's steadfast love, and not because a melody was in David's head needing to come out.
We know grace in Jesus and His atoning death and resurrection satisfied the justice of God. We should think on that and be quick to praise! Jesus is the steadfast love of God. Jesus is the King of Kings Who has made us right with God and Who will return to set this world right! Jesus gives us reason to be a people of praise.