אַ֭חֲרָיו יָאִ֣יר נָתִ֑יב יַחְשֹׁ֖ב תְּה֣וֹם לְשֵׂיבָֽה׃
He maketh a path to shine after him; One would think the deep to be hoary.
Rashi on Job
He makes a path shine after him When he swims and floats in the sea, he makes the path of the deep shine, for at the time he swims, there is no water because of the speed of his swimming.
Rashi on Job
he considers the deep to be hoary To him, the deep is considered to be weak and feeble.