He is the chief of the ways of God - In size and strength. The word rendered "chief" is used in a similar sense in Numbers 24:20, "Amalek was the first of the nations;" that is, one of the most powerful and mighty of the nations.
He that made him can make his sword approach unto him - According to this translation, the sense is, that God had power over him, notwithstanding his great strength and size, and could take his life when he pleased. Yet this, though it would be a correct sentiment, does not seem to be that which the connection demands. That would seem to require some allusion to the strength of the animal; and accordingly, the translation suggested by Bochart, and adopted substantially by Rosenmuller, Umbreit, Noyes, Schultens, Prof. Lee, and others, is to be preferred - "He that made him furnished him with a sword." The allusion then would be to his strong, sharp teeth, hearing a resemblance to a sword, and designed either for defense or for the purpose of cutting the long grass on which it fed when on the land. The propriety of this interpretation may be seen vindicated at length in Bochart, "Hieroz." P. ii. Lib. v. c. xv. pp. 766, 762. The ἅρπη harpē, i. e. the sickle or scythe, was ascribed to the hippopotamus by some of the Greek writers. Thus, Nicander, "Theriacon," verse 566:
Η ἵππον, τὸν Νεῖλος ύπερ Σάιν αἰθαλοεσσαν
Βόσκει, ἀρούρησιν δὲ κακὴν ἐπιβάλλεται
ἍΡΠΗΝ.
Ee hippon, ton Neilos huper Sain aithaloessan
Boskei, arourēsin de kakēn epiballetai.
Harpēn
On this passage the Scholiast remarks, "The ἅρπη harpē, means a sickle, and the teeth of the hippopotamus are so called - teaching that this animal consumes (τρώγει trōgei) the harvest." See Bochart also for other examples. A slight inspection of the "cut" will show with what propriety it is said of the Creator of the hippopotamus, that he had armed him with a sickle, or sword.

He is the chief of the ways of God - The largest, strongest, and swiftest quadruped that God has formed.
He that made him - No power of man or beast can overcome him. God alone can overcome him, and God alone could make his sword (of extinction) approach to him.

(h) He [is] the chief of the ways of God: (i) he that made him can make his sword to approach [unto him].
(h) He is one of the chief works of God among the beasts.
(i) Though man dare not come near him, yet God can kill him.

He is the chief of the ways of God,.... Or the beginning of them, that is, of the works of God in creation; which must be restrained to animals, otherwise there were works wrought before any of them were created. There were none made before the fifth day of the creation, and on that day was the river horse made; in which respect it has the preference to the elephant, not made till the sixth day. But if this phrase is expressive of the superior excellency of behemoth over other works of God, as it seems to be, it must be limited to the kind of which it is; otherwise man is the chief of all God's ways or works, made either on the fifth or sixth day: and so as the elephant may be observed to be the chief of the beasts of the earth, or of land animals, for its largeness and strength, its sagacity, docility, gentleness, and the like; so the river horse may be said to be the chief of its kind, of the aquatic animals, or of the amphibious ones, for the bulk of its body, which is not unlike that of the elephant, as says Diodorus Siculus (q); and it has been by some called the Egyptian elephant (r); and also from its great sagacity, of which instances are given by some writers (s). However, it is one of the chief works of God, or a famous, excellent, and remarkable one, which may be the sense of the expression; see Numbers 24:20. It might be remarked in favour of the elephant, that it seems to have its name from the first and chief; as the first letter in the Hebrew alphabet is called "aleph"; unless it should have its name from this root, on account of its docility;
he that made him can make his sword to approach unto him; not the sword of God, as if this creature could not be killed by any but by him that made it; for whether the elephant or river horse be understood, they are both to be taken and slain: but the sword of behemoth is that which he himself is furnished with; which some understand of the trunk of the elephant, with which he defends himself and annoys others; but that has no likeness of a sword. Bochart (t) renders the word by "harpe", which signifies a crooked instrument, sickle or scythe; and interprets it of the teeth of the river horse, which are sharp and long, and bent like a scythe. That which Thevenot (u) saw had four great teeth in the lower jaw, half a foot long, two whereof were crooked; and one on each side of the jaw; the other two were straight, and of the same length as the crooked, but standing out in the length: see the figure of it in Scheuchzer (w); by which it also appears to have six teeth. Another traveller says (x), of the teeth of the sea horse, that they are round like a bow, and about sixteen inches long, and in the biggest part more than six inches about: but another relation (y) agrees more nearly with Thevenot and Scheuchzer; that four of its teeth are longer than the rest, two in the upper jaw, one on each side, and two more in the under; these last are four or five inches long, the other two shorter; with which it mows down the corn and grass in great quantities: so that Diodorus Siculus (z) observes, that if this animal was very fruitful, and brought forth many young and frequently, the fields in Egypt would be utterly destroyed. This interpretation agrees with what follows.
(q) Ut supra. (Bibliothec. l. 2. p. 136. & l. 3. p. 173. 174. 175.) (r) Achilles Tatius, l. 4. (s) Ammian. Marcellin. Plin. Solin. ut supra. Vid. Plin. l. 28. c. 8. (t) Ut supra, (Apud Hierozoic. par. 2. l. 5. c. 14.) col. 760. (u) Travels, part 1. c. 72. (w) Physic. Sacr. tab. 532. (x) Dampier's Voyages, vol. 2. part 2. p. 105. (y) Capt. Rogers apud Dampier, ib. p. 106. (z) Ut supra. (Bibliothec. l. 2. p. 136. & l. 3. p. 173. 174. 175.)

Chief of the works of God; so "ways" (Job 26:14; Proverbs 8:22).
can make his sword to approach--rather, "has furnished him with his sword" (harpe), namely, the sickle-like teeth with which he cuts down grain. English Version, however, is literally right.

19 He is the firstling of the ways of God;
He, his Maker, reached to him his sword.
20 For the mountains bring forth food for him,
And all the beasts of the field play beside him.
21 Under the lote-trees he lieth down,
In covert of reeds and marsh.
22 Lote-trees cover him as shade,
The willows of the brook encompass him.
23 Behold, if the stream is strong, he doth not quake;
He remaineth cheerful, if a Jordan breaketh forth upon his mouth.
24 Just catch him while he is looking,
With snares let one pierce his nose!
God's ways is the name given to God's operations as the Creator of the world in Job 40:19 (comp. Job 26:14, where His acts as the Ruler of the world are included); and the firstling of these ways is called the Behmth, not as one of the first in point of time, but one of the hugest creatures, un chef-d'oeuvre de Dieu (Bochart); ראשׁית not as Proverbs 8:22; Numbers 24:20, of the priority of time, but as Amos 6:1, Amos 6:6, of rank. The art. in העשׁו is, without the pronominal suff. being meant as an accusative (Ew. 290, d), equal to a demonstrative pronoun (comp. Ges. 109, init): this its Creator (but so that "this" does not refer back so much as forwards). It is not meant that He reached His sword to behmoth, but (on which account לו is intentionally wanting) that He brought forth, i.e., created, its (behmoth's) peculiar sword, viz., the gigantic incisors ranged opposite one another, with which it grazes upon the meadow as with a sickle: ἀρούρῃσιν κακὴν ἐπιβάλλεται ἅρπην (Nicander, Theriac. 566), ἅρπη is exactly the sickle-shaped Egyptian sword (harpu = חרב). Vegetable food (to which its teeth are adapted) is appointed to the behmoth: "for the mountains produce food for him;" it is the herbage of the hills (which is scanty in the lower and more abundant in the upper valley of the Nile) that is intended, after which this uncouth animal climbs (vid., Schlottm.). בּוּל is neither a contraction of יבוּל (Ges.), nor a corruption of it (Ew.), but Hebraeo-Arab. = baul, produce, from bâla, to beget, comp. aballa, to bear fruit (prop. seed, bulal), root בל, to soak, wet, mix.
(Note: Whether בּליל, Job 6:5; Job 24:6, signifies mixed provender (farrago), or perhaps ripe fruit, i.e., grain, so that jabol, Judges 19:21, in the signification "he gave dry provender consisting of barley-grain," would be the opposite of the jahushsh (יחשׁ) of the present day, "he gives green provender consisting of green grass or green barley, hashı̂sh," as Wetzst. supposes, vid., on Isaiah 30:24.)
Job 40:20 describes how harmless, and if unmolested, inoffensive, the animal is; שׁם there, viz., while it is grazing.
In Job 40:21 Saadia correctly translates: Arab. tḥt 'l-ḍâl; and Job 40:22, Abulwalid: Arab. ygṭı̂h 'l-ḍl mdlllâ lh, tegit eum lotus obumbrans eum, by interpreting Arab. 'l-ḍl, more correctly Arab. 'l-ḍâl, with es-sidr el-berrı̂, i.e., Rhamnus silvestris (Rhamnus Lotus, Linn.), in connection with which Schultens' observation is to be noticed: Cave intelligas lotum Aegyptiam s. plantam Niloticam quam Arabes Arab. nûfr. The fact that the wild animals of the steppe seek the shade of the lote-tree, Schultens has supported by passages from the poets. The lotus is found not only in Syria, but also in Egypt, and the whole of Africa.
(Note: The Arab. ḍâl or Dûm-tree, which likes hot and damp valleys, and hence is found much on the northern, and in great numbers on the eastern, shores of the Sea of Galilee, is called in the present day sidra, collect. sidr; and its fruit, a small yellow apple, dûma, collect. dûm, perhaps "the not ending, perennial," because the fruit of the previous year only falls from the tree when that of the present year is ripe. Around Bagdad, as they told me, the Dûm-tree bears twice a year. In Egypt its fruit is called nebq (נבק, not nibq as in Freytag), and the tree is there far stronger and taller than in Syria, where it is seldom more than about four and twenty feet high. Only in the Wdi 's-sidr on the mountains of Judaea have I seen several unusually large trunks. The Kms places the signification "the sweet Dûm-tree" first of all to Arab. ḍâl, and then "the wild D." In hotter regions there may also be a superior kind with fine fruit, in Syria it is only wild - Neshwn (ii. 192) says: "dâla, collect. dâl, is the wild Dûm-tree," - yet I have always found its fruit sweet and pleasant to the taste. - Wetzst.)
The plur. is formed from the primary form צאל, as שׁקמים from שׁקם, Olsh. 148, b; the single tree was perhaps called צאלה (= Arab. ḍâlt), as שׁקמה (Ew. 189, h). Ammianus Marc. xxii. 15 coincides with Job 40:21: Inter arundines celsas et squalentes nimia densitate haec bellua cubilia ponit. צללו, Job 40:22 (resolved from צלּו, as גּללו, Job 20:7, from גּלּו),
(Note: Forms like גּלל, צלל, are unknown to the language, because it was more natural for ease of pronunciation to make the primary form סבבּ into סב than into סבב, גּללו (vid., p. 449), צללו, might more readily be referred to גּלל, צלל (in which the first a is a helping vowel, and the second a root vowel); but although the form קטל and the segolate forms completely pass into one another in inflection, still there does not exist a safe example in favour of the change of vowels of קטל into קטלי; wherefore we have also derived אגלי, Job 38:28, from אגל, not from אגל, although, moreover, ̇̇ frequently enough alternates with ̇̇ (e.g., ישׁעך), and a transition into ̇̇ of the ̇̇ weakened from ̇̇ (e.g., ידכם) also occurs. But there are no forms like נטפי = נטפי from נטף in reality, although they would be possible according to the laws of vowels. In Ges. Handwrterb. (1863) גּללו stands under גּלל (according to the form לבב, which, however, forms לבבו) and צללו under סלל ( a rare noun-form, which does not occur at all from verbs double Ayin).)
is in apposition with the subj.: Lote-trees cover it as its shade (shading it). The double play of words in Job 40:22 is not reproduced in the English translation.
הן, Job 40:23, pointing to something possible, obtains almost the signification of a conditional particle, as Job 12:14; Job 23:8; Isaiah 54:15. The Arabic version appropriately translates Arab. 'n ṭgâ 'l-nhr, for Arab. ṭgâ denotes exactly like עשׁק, excessive, insolent behaviour, and is then, as also Arab. dlm, ‛tâ, and other verbs given by Schultens, transferred from the sphere of ethics to the overflow of a river beyond its banks, to the rush of raging waters, to the rising and bursting forth of swollen streams. It does not, however, terrify the behmoth, which can live as well in the water as on the land; לא יחפּוז, properly, it does not spring up before it, is not disturbed by it. Instead of the Jordan, Job 40:23, especially in connection with יגיח, the 'Gaihn (the Oxus) or the 'Gaihn (the Pyramus) might have been mentioned, which have their names from the growing force with which they burst forth from their sources (גּיח, גּוּח, comp. 'gâcha, to wash away). But in order to express the notion of a powerful and at times deep-swelling stream, the poet prefers the ירדּן of his fatherland, which moreover, does not lie so very far from the scene, according to the conception at least, since all the wadis in its neighbourhood flow directly or indirectly (as Wdi el-Meddn, the boundary river between the district of Suwt and the Nukra plain) into the Jordan. For ירדּן (perhaps from ירד)
(Note: Certainly one would have expected ירדּן like גּרזן, while ירדּן like יעבּץ, יעזר, appears formed from רדן; nevertheless ירדּן (with changeable Ssere) can be understood as a change of vowel from ירדּן (comp. ישׁב for ישׁב).)
does not here signify a stream (rising in the mountain) in general; the name is not deprived of its geographical definiteness, but is a particularizing expression of the notion given above.
The description closes in Job 40:24 with the ironical challenge: in its sight (בּעיניו as Proverbs 1:17) let one (for once) catch it; let one lay a snare which, when it goes into it, shall spring together and pierce it in the nose; i.e., neither the open force nor the stratagem, which one employs with effect with other animals, is sufficient to overpower this monster. מוקשׁים is generally rendered as equal to חחים, Isaiah 37:29; Ezekiel 19:4, or at least to the cords drawn through them, but contrary to the uniform usage of the language. The description of the hippopotamus
(Note: Vid., Grehm, Aus dem Leben des Nilpferds, Gartenlaube 1859, Nr. 48, etc.)
is not followed by that of the crocodile, which also elsewhere form a pair, e.g., in Achilles Tatius, iv. 2, 19. Behemoth and leviathan, says Herder, are the pillars of Hercules at the end of the book, the non plus ultra of another world distant from the scene. What the same writer says of the poet, that he does not "mean to furnish any contributions to Pennant's Zoologie or to Linnaeus' Animal Kingdom," the expositor also must assent to.

The chief - He is one of the chief of God's works, in regard of its great bulk and strength.