Behold, if the river is turbulent he is not frightened; he is confident though Jordan rushes against his mouth.
God, for the further proving of his own power and disproving of Job's pretensions, concludes his discourse with the description of two vast and mighty animals, far exceeding man in bulk and strength, one he calls behemoth, the other leviathan. In these verses we have the former described.
Commenting on Job 40:15-24
He taketh it with his eyes,.... Or "can men take him before his eyes?" so Mr. Broughton; and others translate it to the same purpose; no, he is not to be taken openly, but privately, by some insidious crafty methods; whether it be understood of the elephant or river horse; elephants, according to Strabo (q) and Pliny (r) were taken in pits dug for them...
Rather, "(Though) a river be violent (overflow), he trembleth not"; (for though living on land, he can live in the water, too); he is secure, though a Jordan swell up to his mouth. "Jordan" is used for any great river (consonant with the "behemoth"), being a poetical generalization (see on Job 40:15).