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 - being, according to Abdollatiph (see Ros.), about half a cubit in length. In the lower part, says he, it is thick, "equalling the extremities of the fingers;" and the idea here, according to this, is, that this short, thick, and apparently firm tail, was bent over by the will of the animal as the wind bends the branches of the cedar.
The point of comparison is not the "length," but the fact of its being easily bent over or curved at the pleasure of the animal. Why this, however, should have been mentioned as remarkable, or how the power of the animal in this respect differs from others, is not very apparent. Some, who have supposed the elephant to be here referred to, have understood this of the proboscis. But though "this would be" a remarkable proof of the power of the animal, the language of the original will not admit of it. The Hebrew word (זנב zânâb) is used only to denote the tail. It is "possible" that there may be here an allusion to the unwieldy nature of every part of the animal, and especially to the thickness and inflexibility of the skin and what was remarkable was, that notwithstanding this, this member was entirely at its command. Still, the reason of the comparison is not very clear. The description of the movement of the "tail" here given, would agree much better with some of the extinct orders of animals whose remains have been recently discovered and arranged by Cuvier, than with that of the hippopotamus. Particularly, it would agree with the account of the ichthyosaurus (see Buckland's "Geology, Bridgewater Treatise," vol. i. 133ff), though the other parts of the animal here described would not accord well with this.
The sinews of his stones are wrapped together - Good renders this, "haunches;" Noyes, Prof. Lee, Rosenmuller, and Schultens, "thighs;" and the Septuagint simply has: "his sinews." The Hebrew word used here (פחד pachad) means properly "fear, terror," Exodus 15:16; Job 13:11; and, according to Gesenius, it then means, since "fear" is transferred to cowardice and shame, anything which "causes" shame, and hence, the secret parts. So it is understood here by our translators; but there does not seem to be any good reason for this translation, but there is every reason why it should not be thus rendered. The "object" of the description is to inspire a sense of the "power" of the animal, or of his capacity to inspire terror or dread; and hence, the allusion here is to those parts which were fitted to convey this dread, or this sense of his power - to wit, his strength. The usual meaning of the word, therefore, should be retained, and the sense then would be, "the sinews of his terror," that is, of his parts fitted to inspire terror, "are wrapped together;" are firm, compact, solid. The allusion then is to his thighs or haunches, as being formidable in their aspect, and the seat of strength. The sinews or muscles of these parts seemed to be like a hard-twisted rope; compact, firm, solid, and such as to defy all attempts to overcome them.

He moveth his tail like a cedar - Therefore it was neither the elephant, who has a tail like that of the hog, nor the hippopotamus, whose tail is only about a foot long.
The sinews of his stones - I translate with Mr. Good, and for the same reasons, the sinews of his haunches, which is still more characteristic; as the animal must have excelled in leaping.

He moveth his tail like a cedar,.... 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 (c) 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 (d); 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 (e) speaks of the horse of the Nile, as having a scaly tail; but he seems to confound it with the sea horse. Junius interprets it of its penis, its genital part; to which the Targum in the King's Bible is inclined: and Cicero (f) says, the ancients used to call that the tail; but that of the elephant, according to Aristotle (g), is but small, and not in proportion to the size of its body; and not in sight, and therefore can hardly be thought to be described; though the next clause seems to favour this sense:
the sinews of his stones are wrapped together; if by these are meant the testicles, as some think, so the Targums; the sinews of which were wreathed, implicated and ramified, like branches of trees, as Montanus renders it. Bochart interprets this of the sinews or nerves of the river horse, which having such plenty of them, are exceeding strong; so that, as some report, this creature will with one foot sink a boat (h); I have known him open his mouth, says a traveller (i), and set one tooth on the gunnel of a boat, and another on the second strake from the keel, more than four feet distant, and there bite a hole through the plank, and sink the boat.
(c) Navigat. l. 4. c. 9. (d) Aristot. Plin. Solin. & Isidore ut supra. (See Job 40:16.) (e) Nicet. Choniat. apud Fabrit. Gr. Bibliothec. vol. 6. p. 410. (f) Epist. l. 9. ep. 22. (g) Hist. Amimal. l. 2. c. 1. (h) Apud Hierozoic, par. 2. l. 5. c. 14. col. 758. (i) Dampier's Voyages, vol. 2. part 2. p. 105.

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.

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.