Albert Barnes Commentary Psalms 107:23

"They that go down to the sea in ships, That do business in great waters;" — Psalms 107:23 (ASV)

They that go down to the sea in ships - The scene here changes again. From those that wander in the desert—from those who are in prison—from those who are sick—the eye of the psalmist turns to those who encounter the perils of the ocean, and he finds there occasion for praise to God. The phrase “go down” or “descend” is employed here because the sea is lower than the land, and because we “descend” when we embark on board of a vessel.

That do business ... - Whose business or employment is on the ocean.