This chapter consists entirely of a song that David sings praising God, after God has saved him from his enemies and from Saul.
He says that God is his rock, his shield, and other metaphors for a protector, stating plainly that God has saved him from his enemies.
David said he felt like he was surrounded by death: the underworld of Sheol seemed to be all around him.
But God heard his cries for help. In fire and anger, God moves against David's enemies, making the heavens and the earth quake. God flies on a cherub and covers himself in darkness, with light like coals flaming in front of him.
God's act of saving David is, he says, like parting the Red Sea for Moses all over again.
God draws David out of "many waters," saving him from his enemies forever, and bringing him into a "broad place."
God, says David, rewarded him for his righteousness. David claims that he followed God's rules and didn't deviate from them.
God appears to people they way they themselves are—if they're loyal, God will be loyal. If they're pure, God will be pure. But if they're wicked and perverse, God will be wicked and perverse.
If people are humble, God will save them, but, if they're proud, he'll look to take them down.
David praises God for giving him his strength and his ability to rule and compete in combat, and for granting him victory over his enemies.
Even, says David, foreigners were made to serve David—thanks to God's help. The other nation's were cowed, and David remained Israel's head-of-state.
David ends by further praising God for saving him and helping him, calling him a "tower of salvation."