Then the earth shook and quaked; the foundations of the mountains trembled; they shook because he burned with anger. Psalm 18:7

Then the earth shook and quaked;
the foundations of the mountains trembled;
they shook because he burned with anger.
-Psalm 18:7

Psalm 18, Title:

Praise for Deliverance
David’s Song of Thanks
A Song of Victory
Song of Thanks for Being Kept Safe
Royal Thanksgiving for Victory

Psalm 18
David's hymn of praise to God for his deliverance from all his enemies, has an appropriate place in the present group of Psalms, which speak of resurrection after suffering.
-Christopher Wordsworth

Psalm 18
John Brown (1853):
It is a magnificent eucharistic ode. It begins with a celebration of the glorious perfections of the Divinity, whose assistance the speaker had so often experienced.
He describes, or rather, he delineates, his perils, the power of his enemies, his sudden deliverance from them, and the indignation and power of his divine deliverer manifested in their overthrow.
He paints these in so lively colors, that while we read we seem to see the lightning, to hear the thunders, to feel the earthquake. He afterwards describes his victories, so that we seem to be eye-witnesses of them, and take part in them.
He predicts a wide extended empire, and concludes with a lofty expression of grateful adoration of Jehovah, the Author of all his deliverances and triumphs. The style is highly oratorical and poetical, sublime, and full of uncommon figures of speech
It is the natural language of a person of the highest mental endowments, under a divine inspiration, deeply affected by remarkable divine benefits, and filled with the most lofty conceptions of the divine character and dispensations.

The prayer of a single saint is sometimes followed with wonderful effects; "In my distress I called upon the Lord, and cried unto my God: he heard my voice out of his temple, and my cry came before him, even into his ears."
-John Flayel
"Then the earth shook and trembled." (Psalm 18:7) The word גּעשׂ signifies, to move or shake violently: it is employed, also, to denote the reeling and staggering of a drunken man. Jeremiah 25:16.
- John Morison
Let no appearing impossibilities make you question God's accomplishment of any of his gracious words. Though you cannot see how the thing can be done, 'tis enough if God hath said that he will do it. There can be no obstructions to promised salvation which we need to fear.
-T. Cruso