John Gill's Exposition of the Whole Bible
Job 40:19
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 אלף, 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.)