This is one of David’s battle hymns with quotations from several other psalms. It draws the image of someone fully confident in a God who has already shown His great power against enemies of the Covenant. David never forgets that the only value of Israel as a nation is how their covenant life reveals Jehovah.
David begins with lavish praise for Jehovah from a warrior’s point of view. Indeed, the only reason David goes to war is because it is his divine calling. Were it not for the Lord’s anointing, David would have no competence at all in battle. But He is much more than a mere war deity, for He teaches David compassion and protection, how to be a refuge and deliverer, a shield and fortress. God has been these things to David first. Without God, David would hardly be king of anything; no one would follow him.
Indeed, there is nothing in mankind the merits any notice from God, much less the vast measureless blessings He offers under the Covenant. The whole thing rests firmly in God’s own character and purpose to reveal Himself.
So David boldly requests that Jehovah Himself come and lead them into battle. Where God is, the earth is afire with His glory. David notes how God’s Presence has the effect of long-range weapons used to whittle the enemy forces down before the actual melee begins. But His arrows are more like lightning strikes. And should things still get difficult, David asks that the Lord deliver him personally. Even should the enemy come on like a flood, David is confident he will prevail under God’s command. These enemies fail because they do not know Jehovah, and thus their whole existence is one big lie against Him.
And after the victory is won, David’s first act is not gathering plunder, but sitting down to compose a new worship song to the Lord. This is the One who decides which kings and nations survive human warfare. David’s trust is fully warranted.
Indeed, it is God’s revealed nature to bring down those who ignore His revelation and attack Israel. He does this as part of His Covenant promises. It’s the same promises that protects and prospers each new generation: sons who grow stout like trees and daughters who are as solid and supportive as cornerstones of palaces. This is the God who pours out prosperity and plenty, with abundant food and trade goods. This is Jehovah who protects from plundering raiders, whose nation will never be refugees in flight. Their streets are peaceful. This is why David is willing to go to war.
This is the picture of the nation that serves Jehovah.