For his shade the lotus trees cover him; the willows of the brook surround him.
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
Behold, he drinketh up a river, and hasteth not,.... The elephant is indeed a very thirsty animal, and drinks largely; the philosopher (l) says it drinks nine Macedonian bushels at a feeding, and that it will drink fourteen Macedonian measures of water at once, and eight more at noon; but to drink up a river seems to be too great an hyperbole; wherefore the words...
The willows of the brook compass him - This would agree well enough with the hippopotamus.