“The LORD also thundered in the heavens, and the Most High uttered his voice, hailstones and coals of fire. […] Then the channels of the sea were seen, and the foundations of the world were laid bare, at your rebuke, O LORD, at the blast of the breath of your nostrils” (Psalm 18:13, 15).
David wrote Psalm 18 near the beginning of his reign, after he had experienced God delivering him from all his enemies. He had been on the run for years from Saul, but now Saul had died, and David was finally king over all Israel. It would have been easy to take the credit for himself, to offer a token sacrifice of thanksgiving to God and then make himself out to be the mightiest warrior in the land. But instead, he chose to honor God. Songs like Psalm 18 show that David understood well where his success had truly come from.
This psalm is filled with vivid imagery of God as the true mighty warrior. David names Him his rock, his fortress, his deliverer, and his shield, among other things. He describes his feelings of despair as death closed in around him, and then he rejoices because God delivered him. He tells of the earth shaking, of God coming down from heaven riding on an angel, breathing fire as He descends. He tears the earth apart to snatch His faithful servant out of the clutches of death. He sets His righteous one on a firm rock and trains him in battle, such that no enemy can stand against him. All the nations come to fear this mighty king, for God has made him great.
The picture this psalm paints is incredible. God is powerful, far more than we can ever comprehend. The earth answers to Him, and nothing can stand against Him. He brought David out of every trouble, because David recognized that his strength always came from God. We serve the same God, and He delivers us with that same strength.