There is a direct correlation in the scriptures between David and Christ. Jesus is actually called the "Son of David", and is indeed a direct descendant according to the gospel's genealogies. More than that though is the promised fulfillment of the promise God made to David that an eternal ruler would sit on his throne. Jesus is that eternal ruler, whose kingdom shall have no end.
In one of the last stories (above) f David given to us in 2 Samuel, we are given another random and non-chronological account of his defeating the Philistines. It is intentionally generic to remind us that David was a hero (albeit imperfect) and a warrior for the kingdom of God.
God has saved us to be worshippers and warriors for the kingdom of God as well. So even as Christ fulfills David's legacy, when we are in Christ we inherited the victory that is won in Christ as well. The battle is already won. We are now simply fulfilling the mop up operations that God has for us, in order to work out by faith the victory that Jesus has already granted us!
In Prayer Today:
Thank Jesus that the battle is already won!