Albert Barnes Commentary Psalms 107:26

"They mount up to the heavens, they go down again to the depths: Their soul melteth away because of trouble." — Psalms 107:26 (ASV)

They mount up to the heaven - The mariners. That it refers to the seamen, and not to the waves, is apparent from the close of the verse: their soul is melted.

They go down again to the depths - The word here is different from that used in (Psalms 107:24), and rendered “deep,” but the idea is essentially the same. It is the sea or ocean considered as “deep;” as bottomless. The idea here is, that they seem to descend into the very depths of the ocean.

Their soul is melted because of trouble - It seems to dissolve; it loses all its vigor; it faints. The word used - מוג mûg - means to melt; to flow down; to soften; and is then applied to the heart or mind that loses its courage or vigor by fear or terror (Exodus 15:15; Joshua 2:9, 2:24; Nahum 1:5). The “trouble” here referred to is that which arises from fear and danger.