A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
job 41:1(Job 41:1-34)
leviathan--literally, "the twisted animal," gathering itself in folds: a synonym to the Thannin (Job 3:8, Margin; see Psa 74:14; type of the Egyptian tyrant; Psa 104:26; Isa 27:1; the Babylon tyrant). A poetical generalization for all cetacean, serpentine, and saurian monsters (see on Job 40:15, hence all the description applies to no one animal); especially the crocodile; which is naturally described after the river horse, as both are found in the Nile.
tongue . . . lettest down?--The crocodile has no tongue, or a very small one cleaving to the lower jaw. But as in fishing the tongue of the fish draws the baited hook to it, God asks, Canst thou in like manner take leviathan?
job 41:2hook--rather, "a rope of rushes."
thorn--rather, a "ring" or "hook." So wild beasts were led about when caught (Isa 37:29; Eze 29:4); fishes also were secured thus and thrown into the water to keep them alive.
job 41:3soft words--that thou mayest spare his life. No: he is untamable.
job 41:4Can he be tamed for domestic use (so Job 39:10-12)?
job 41:5a bird?--that is, tamed.
job 41:6Rather, "partners" (namely, in fishing).
make a banquet--The parallelism rather supports UMBREIT, "Do partners (in trade) desire to purchase him?" So the Hebrew (Deu 2:6).
merchants--literally, "Canaanites," who were great merchants (Hos 12:7, Margin).
job 41:7His hide is not penetrable, as that of fishes.
job 41:8If thou lay . . . thou wilt have reason ever to remember . . . and thou wilt never try it again.
job 41:9the hope--of taking him.
cast down--with fear "at the (mere) sight of him."
job 41:10fierce--courageous. If a man dare attack one of My creatures (Gen 49:9; Num 24:9), who will dare (as Job has wished) oppose himself (Psa 2:2) to Me, the Creator? This is the main drift of the description of leviathan.
job 41:11prevented--done Me a favor first: anticipated Me with service (Psa 21:3). None can call Me to account ("stand before Me," Job 41:10) as unjust, because I have withdrawn favors from him (as in Job's case): for none has laid Me under a prior obligation by conferring on Me something which was not already My own. What can man give to Him who possesses all, including man himself? Man cannot constrain the creature to be his "servant" (Job 41:4), much less the Creator.
job 41:12I will not conceal--a resumption of the description broken off by the digression, which formed an agreeable change.
his power--literally, "the way," that is, true proportion or expression of his strength (so Hebrew, Deu 19:4).
comely proportion--literally, "the comeliness of his structure" (his apparatus: so "suit of apparel" Jdg 17:10) [MAURER]. UMBREIT translates, "his armor." But that follows after.
job 41:13discover--rather, "uncover the surface" of his garment (skin, Job 10:11): strip off the hard outer coat with which the inner skin is covered.
with--rather, "within his double jaws"; literally, "bridle"; hence that into which the bridle is put, the double row of teeth; but "bridle" is used to imply that none dare put his hand in to insert a bridle where in other animals it is placed (Job 41:4; Job 39:10).
job 41:14doors of . . . face--his mouth. His teeth are sixty in number, larger in proportion than his body, some standing out, some serrated, fitting into each other like a comb [BOCHART].
job 41:15Rather, his "furrows of shields" (as "tubes," "channels," see on Job 40:18), are, &c., that is, the rows of scales, like shields covering him: he has seventeen such rows.
shut up--firmly closed together. A musket ball cannot penetrate him, save in the eye, throat, and belly.
job 41:18Translate: "his sneezing, causeth a light to shine." Amphibious animals, emerging after having long held their breath under water, respire by violently expelling the breath like one sneezing: in the effort the eyes which are usually directed towards the sun, seem to flash fire; or it is the expelled breath that, in the sun, seems to emit light.
eyelids of morning--The Egyptian hieroglyphics paint the eyes of the crocodile as the symbol for morning, because the eyes appear the first thing, before the whole body emerges from the deep [HorÃ&brvbr; HierogliphicÃ&brvbr; 1.65. BOCHART].
job 41:19burning lamps--"torches"; namely, in respiring (Job 41:18), seem to go out.
job 41:20seething--boiling: literally, "blown under," under which a fire is blown.
job 41:21kindleth coals--poetical imagery (Psa 18:8).
job 41:22remaineth--abideth permanently. His chief strength is in the neck.
sorrow--anxiety or dismay personified.
is turned into joy--rather, "danceth," "exulteth"; wherever he goes, he spreads terror "before him."
job 41:23flakes--rather, "dewlaps"; that which falls down (Margin). They are "joined" fast and firm, together, not hanging loose, as in the ox.
are firm--UMBREIT and MAURER, "are spread."
in themselves--rather, "upon him."
job 41:24heart--"In large beasts which are less acute in feeling, there is great firmness of the heart, and slower motion" [BOCHART]. The nether millstone, on which the upper turns, is especially hard.
job 41:25he--the crocodile; a type of the awe which the Creator inspires when He rises in wrath.
breakings--namely, of the mind, that is, terror.
purify themselves--rather, "they wander from the way," that is, flee away bewildered [MAURER and UMBREIT].
job 41:26cannot hold--on his hard skin.
habergeon--coat of mail; avail must be taken by zeugma out of "hold," as the verb in the second clause: "hold" cannot apply to the "coat of mail."
job 41:27iron . . . brass--namely, weapons.
job 41:28arrow--literally, "son of the bow"; Oriental imagery (Lam 3:13; Margin).
stubble--Arrows produce no more effect than it would to throw stubble at him.
job 41:29Darts--rather, "clubs"; darts have been already mentioned (Job 41:26).
job 41:30stones--rather, "potsherds," that is, the sharp and pointed scales on the belly, like broken pieces of pottery.
sharp-pointed things--rather, "a threshing instrument," but not on the fruits of the earth, but "on the mire"; irony. When he lies on the mire, he leaves the marks of his scales so imprinted on it, that one might fancy a threshing instrument with its sharp teeth had been drawn over it (Isa 28:27).
job 41:31Whenever he moves.
sea--the Nile (Isa 19:5; Nah 3:8).
pot of ointment--the vessel in which it is mixed. Appropriate to the crocodile, which emits a musky smell.
job 41:32path--the foam on his track.
hoary--as hair of the aged.
job 41:33who--being one who, &c.
job 41:34beholdeth--as their superior.
children of pride--the proud and fierce beasts. So Job 28:8; Hebrew, "sons of pride." To humble the pride of man and to teach implicit submission, is the aim of Jehovah's speech and of the book; therefore with this as to leviathan, the type of God in His lordship over creation, He closes.