Charles Ellicott Commentary Psalms 104:6

"Thou coveredst it with the deep as with a vesture; The waters stood above the mountains." — Psalms 104:6 (ASV)

The deep. —The water-world is first considered as a vast garment wrapped round the earth, so that the mountain-tops are covered. But here it is beyond its rightful limits, and the Divine rebuke forces it to withdraw within narrower limits.

It is noticeable that the idea of chaos finds no place in the poetic conception of the world’s genesis. The primitive world is not formless, but has its mountains and valleys already existing, though submerged beneath the sea.