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 39:1(Job 39:1-30)
Even wild beasts, cut off from all care of man, are cared for by God at their seasons of greatest need. Their instinct comes direct from God and guides them to help themselves in parturition; the very time when the herdsman is most anxious for his herds.
wild goats--ibex (Psa 104:18; Sa1 24:2).
hinds--fawns; most timid and defenseless animals, yet cared for by God.
job 39:2They bring forth with ease and do not need to reckon the months of pregnancy, as the shepherd does in the case of his flocks.
job 39:3bow themselves--in parturition; bend on their knees (Sa1 4:19).
bring forth--literally, "cause their young to cleave the womb and break forth."
sorrows--their young ones, the cause of their momentary pains.
job 39:4are in good liking--in good condition, grow up strong.
with corn--rather, "in the field," without man's care.
return not--being able to provide for themselves.
job 39:5wild ass--Two different Hebrew words are here used for the same animal, "the ass of the woods" and "the wild ass." (See on Job 6:5; Job 11:12; Job 24:5; and Jer 2:24).
loosed the bands--given its liberty to. Man can rob animals of freedom, but not, as God, give freedom, combined with subordination to fixed laws.
job 39:6barren--literally, "salt," that is, unfruitful. (So Psa 107:34, Margin.)
job 39:7multitude--rather, "din"; he sets it at defiance, being far away from it in the freedom of the wilderness.
driver--who urges on the tame ass to work. The wild ass is the symbol of uncontrolled freedom in the East; even kings have, therefore, added its name to them.
job 39:8The range--literally, "searching," "that which it finds by searching is his pasture."
job 39:9unicorn--PLINY [Natural History, 8.21], mentions such an animal; its figure is found depicted in the ruins of Persepolis. The Hebrew reem conveys the idea of loftiness and power (compare Ramah; Indian, Ram; Latin, Roma). The rhinoceros was perhaps the original type of the unicorn. The Arab rim is a two-horned animal. Sometimes "unicorn" or reem is a mere poetical symbol or abstraction; but the buffalo is the animal referred to here, from the contrast to the tame ox, used in ploughing (Job 39:10, Job 39:12).
abide--literally, "pass the night."
crib-- (Isa 1:3).
job 39:10his band--fastened to the horns, as its chief strength lies in the head and shoulders.
after thee--obedient to thee; willing to follow, instead of being goaded on before thee.
job 39:11thy labour--rustic work.
seed--produce (Sa1 8:15).
into thy barn--rather, "gather (the contents of) thy threshing-floor" [MAURER]; the corn threshed on it.
job 39:13Rather, "the wing of the ostrich hen"--literally, "the crying bird"; as the Arab name for it means "song"; referring to its night cries (Job 30:29; Mic 1:8) vibrating joyously. "Is it not like the quill and feathers of the pious bird" (the stork)? [UMBREIT]. The vibrating, quivering wing, serving for sail and oar at once, is characteristic of the ostrich in full course. Its white and black feathers in the wing and tail are like the stork's. But, unlike that bird, the symbol of parental love in the East, it with seeming want of natural (pious) affection deserts its young. Both birds are poetically called by descriptive, instead of their usual appellative, names.
job 39:14Yet (unlike the stork) she "leaveth," &c. Hence called by the Arabs "the impious bird." However, the fact is, she lays her eggs with great care and hatches them, as other birds do; but in hot countries the eggs do not need so constant incubation; she therefore often leaves them and sometimes forgets the place on her return. Moreover, the outer eggs, intended for food, she feeds to her young; these eggs, lying separate in the sand, exposed to the sun, gave rise to the idea of her altogether leaving them. God describes her as she seems to man; implying, though she may seem foolishly to neglect her young, yet really she is guided by a sure instinct from God, as much as animals of instincts widely different.
job 39:16On a slight noise she often forsakes her eggs, and returns not, as if she were "hardened towards her young."
her labour--in producing eggs, is in vain, (yet) she has not disquietude (about her young), unlike other birds, who, if one egg and another are taken away, will go on laying till their full number is made up.
job 39:17wisdom--such as God gives to other animals, and to man (Job 35:11). The Arab proverb is, "foolish as an ostrich." Yet her very seeming want of wisdom is not without wise design of God, though man cannot see it; just as in the trials of the godly, which seem so unreasonable to Job, there lies hid a wise design.
job 39:18Notwithstanding her deficiencies, she has distinguishing excellences.
lifteth . . . herself--for running; she cannot mount in the air. GESENIUS translates: "lashes herself" up to her course by flapping her wings. The old versions favor English Version, and the parallel "scorneth" answers to her proudly "lifting up herself."
job 39:19The allusion to "the horse" (Job 39:18), suggests the description of him. Arab poets delight in praising the horse; yet it is not mentioned in the possessions of Job (Job 1:3; Job 42:12). It seems to have been at the time chiefly used for war, rather than "domestic purposes."
thunder--poetically for, "he with arched neck inspires fear as thunder does." Translate, "majesty" [UMBREIT]. Rather "the trembling, quivering mane," answering to the "vibrating wing" of the ostrich (see on Job 39:13) [MAURER]. "Mane" in Greek also is from a root meaning "fear." English Version is more sublime.
job 39:20make . . . afraid--rather, "canst thou (as I do) make him spring as the locust?" So in Joe 2:4, the comparison is between locusts and war-horses. The heads of the two are so similar that the Italians call the locusts cavaletta, "little horse."
job 39:21valley--where the battle is joined.
goeth on--goeth forth (Num 1:3; Num 21:23).
job 39:23quiver--for the arrows, which they contain, and which are directed "against him."
glittering spear--literally, "glittering of the spear," like "lightning of the spear" (Hab 3:11).
job 39:24swalloweth--Fretting with impatience, he draws the ground towards him with his hoof, as if he would swallow it. The parallelism shows this to be the sense; not as MAURER, "scours over it."
neither believeth--for joy. Rather, "he will not stand still, when the note of the trumpet (soundeth)."
job 39:25saith--poetically applied to his mettlesome neighing, whereby he shows his love of the battle.
smelleth--snuffeth; discerneth (Isa 11:3, Margin).
job 39:26The instinct by which some birds migrate to warmer climes before winter. Rapid flying peculiarly characterizes the whole hawk genus.
job 39:27eagle--It flies highest of all birds: thence called "the bird of heaven."
job 39:28abideth--securely (Psa 91:1); it occupies the same abode mostly for life.
crag--literally, "tooth" (Sa1 14:5, Margin).
strong place--citadel, fastness.
job 39:29seeketh--is on the lookout for.
behold--The eagle descries its prey at an astonishing distance, by sight, rather than smell.
job 39:30Quoted partly by Jesus Christ (Mat 24:28). The food of young eagles is the blood of victims brought by the parent, when they are still too feeble to devour flesh.
slain--As the vulture chiefly feeds on carcasses, it is included probably in the eagle genus.
He had paused for a reply, but Job was silent.