Job 40:17

“He moveth his tail like a cedar, etc.] To which it is compared, not for the length and largeness of it; for the tail both of the elephant and of the river horse is short; though Vartomannus f1468 says, the tail of the elephant is like a buffalo’s, and is four hands long, and thin of hair: but because of the smoothness, roundness, thickness, and firmness of it; such is the tail of the river horse, being like that of a hog or boar f1469; which is crooked, twisted, and which it is said to turn back and about at pleasure, as the word used is thought to signify. Aben Ezra interprets it, “maketh to stand”: that is, stiff and strong, and firm like a cedar. One writer f1470 horse of the Nile, as…”

“like a cedar--As the tempest bends the cedar, so it can move its smooth thick tail [UMBREIT]. But the cedar implies straightness and length, such as do not apply to the river horse's short tail, but perhaps to an extinct species of animal (see on Job 40:15). stones--rather, "thighs." wrapped--firmly twisted together, like a thick rope.”

“He moveth his tail like a cedar - Margin, “setteth up.” The Hebrew word (חפץ châphêts) means “to bend, to curve;” and hence, it commonly denotes “to be inclined, favorably disposed to desire or please.” The obvious meaning here is, that this animal had some remarkable power of “bending” or “curving” its tail, and that there was some resemblance in this to the motion of the cedar-tree when moved by the wind. In “what” this resemblance consisted, or how this was a proof of its power, it is not quite easy to determine. Rosenmuller says that the meaning is, that the tail of the hippopotamus was “smooth, round, thick, and firm,” and in this respect resembled the cedar. The tail is short -…”

“Tail - Which though it be but short, yet when it is erected, is exceeding stiff and strong. Thighs - The sinews of his thighs. His thighs and feet are so sinewy and strong, that one of them is able to break or over - turn a large boat. Job 40:19”

“moveth: or, setteth up the: Job 41:23 Job 40:18”