Charles H. Spurgeon on Psalms 77:16

The depths also were troubled. The depths are mentioned in addition to the waters, to show that the dominion and power of God reach not only to the surface of the waters, but penetrate to the most profound abysses, and agitate and restrain the waters from their lowest bottom. Mollerus.

Verses 16-18. The waters saw thee, but men do not see thee. The depths were troubled, but men say in their heart, There is no God. The clouds poured out water, but men pour not out cries and tears unto God. The skies send out a sound, but men say not, Where is God my Maker? Thine arrows also went abroad, but no arrows of contrition and supplication are sent back by men in return. The voice of thy thunder was in the heaven, but men hear not the louder thunders of the law. The lightnings lightened the world, but the light of truth shines in darkness and the darkness comprehends it not. The earth trembled and shook, but human hearts remain unmoved.

"My heart it shakes not at the wrath

And terrors of a God." George Rogers.

Verse 16-19. As soon as ever the whole Egyptian army was within it, the sea flowed to its own place, and came down with a torrent raised by storms of wind, and encompassed the Egyptians. Showers of rain also came down from the sky, and dreadful thunders and lightning, with flashes of fire. Thunderbolts also were darted upon them; nor was there anything which used to be sent by God upon men, as indications of his wrath, which did not happen at this time; for a dark and dismal might oppressed them. And thus did all these men perish, so that there was not one man left to be a messenger of this calamity to the rest of the Egyptians. Josephus.