Augustine of Hippo

..."They who go down on the sea in ships, doing their business on the mighty waters" (ver. 23); that is, amongst many peoples. For that waters are often put for peoples, the Apocalypse of John is witness, when on John's asking what those waters were, it was answered him, they are peoples. They then who do their business on mighty waters, "they have seen the works of the Lord, and His wonders in the deep" (ver. 24). For what is deeper than human hearts? hence often break forth winds; storms of sedition, and dissensions, disturb the ship.