Travaileth with pain - That is, his sorrows are like the pains of parturition. Eliphaz means to say that he is a constant sufferer.
All his days - It seems difficult to see how they could have ever formed this universal maxim. It is certainly not literally true now; nor was it ever. But in order to convey the doctrine that the wicked would be punished in as pointed and striking a manner as possible, it was made to assume this universal form - meaning that the life of the wicked would be miserable. There is some reason to think that this and what follows to the close of the chapter, is an ancient fragment which Eliphaz rehearses as containing the sentiments of a purer age of the world.
And the number of years is hidden to the oppressor - Wemyss renders this, "and a reckoning of years is laid up for the violent." So, also, Dr. Good. The Vulgate renders it, "and the number of the years of his tyranny is uncertain." Rosenmuller, Cocceius, Drusius, and some others suppose that there should be understood here and repeated the clause occurring in the first hemistich, and that it means, "and in the number of years which are laid up for the violent man, he is tortured with pain." Luther renders it, "and to a tyrant is the number of his years concealed." It is difficult to tell what the passage means. To me, the most probable interpretation is one which I have not met with in any of the books which I have consulted, and which may be thus expressed," the wicked man will be tormented all his days." To one who is an oppressor or tyrant, the number of his years is hidden. He has no security of life. He cannot calculate with any certainty on its continuance. The end is hid. A righteous man may make some calculation, and can see the probable end of his days. He may expect to see an honored old age. But tyrants are so often cut down suddenly; they so frequently perish by assassination, and robbers are so often unexpectedly overcome, that there is no calculation which can be formed in respect to the termination of their course. Their end is hid. They die suddenly and disappear. This suits the connection; and the sentiment is, in the main, in accordance with facts as they occur.

The wicked man travaileth with pain - This is a most forcible truth: a life of sin is a life of misery; and he that Will sin Must suffer. One of the Targums gives it a strange turn: - "All the days of the ungodly Esau, he was expected to repent, but he did not repent; and the number of years was hidden from the sturdy Ishmael." The sense of the original, מתחולל mithcholel, is he torments himself: he is a true heautontimoreumenos, or self-tormentor; and he alone is author of his own sufferings, and of his own ruin.

The wicked man travaileth with pain all [his] days, and the number (m) of years is hidden to the oppressor.
(m) The cruel man is always in danger of death, and is never quiet in conscience.

The wicked man travaileth with pain all his days,.... Either to commit iniquity, which he is at great pains to do, and even to weariness; and, agreeably to the metaphor used, he conceives it in his heart, he travails with it in his mind, and he brings forth falsehood and a lie, what disappoints him, and which issues in death, eternal death, see Psalm 7:14; or to get wealth and riches, in obtaining of which he pierces himself through with many sorrows; and these being like thorns, in using them he gets many a scratch, and has a good deal of trouble, pain, and uneasiness in keeping them, insomuch that he cannot sleep comfortably through fear of losing them; wherefore he does not enjoy that peace, comfort, and happiness, it may be thought he does; and, besides all this, he has many an inward pain and gripe of conscience for his many sins and transgressions, which lie at the door of conscience, and when it is opened rush in, and make sad work, and put him to great pain and distress; for otherwise this cannot be said of every wicked man, that they are in outward pain and distress, or in uncomfortable circumstances, at least in appearance; for of some it is said, "they are not in trouble as other men, neither are they plagued like other men", Psalm 73:5; they live wholly at ease, and are quiet, and die so, at least seemingly: some restrain this to some particular person whom Eliphaz might have in view; the Targum paraphrases it of wicked Esau, who it was expected would repent, but did not; others think that he had in his eye some notorious oppressor, that had lived formerly, or in his time, as Nimrod, the mighty hunter and tyrant, or Chedorlaomer, who held for some years several kings in subjection to him; but it is much if he does not design Job himself; however, he forms the description of the wicked man in such a manner, that it might as near as possible suit his case, and in many things he plainly refers to it: and this is a sad case indeed, for a wicked man to travail in pain all his days in this life, and in the world to come to suffer the pains of hell fire to all eternity; the pains of a woman, to which the allusion is, are but short at most, but those of the wicked man are for life, yea, for ever; and among the rest of his pains of mind, especially in this world, what follows is one, and which gives much uneasiness: and the number of years is hidden to the oppressor; Mr. Broughton renders it, soon numbered years; that is, few, as the years of man's life at most are but few, and those of the oppressor fewer still, since bloody and deceitful men do not live out half the days of the years of man's life, but are oftentimes cut off in the midst of their days; and be they more or fewer, they are all numbered and fixed, and the number of them is with God, and him only; they are fixed and settled by the decree of God, and laid up in his purposes, and reserved for the oppressor; but they are a secret to him, he does not know how long he shall live, or how soon he may die, and then there will be an end of his oppression and tyranny, and of his enjoyment of his wealth and riches unjustly got; and this frets him, and gives him pain, and makes him uneasy; whereas a good man is easy about it, he is willing to wait his appointed time, till his change comes; he is not so much concerned to know the time of his death as to be in a readiness for it. The Targum paraphrases this of Ishmael the mighty: the oppressor is the same with the wicked man in the preceding clause.

travaileth--rather, "trembleth of himself," though there is no real danger [UMBREIT].
and the number of his years, &c.--This gives the reason why the wicked man trembles continually; namely, because he knows not the moment when his life must end.

20 So long as the ungodly liveth he suffereth,
And numbered years are reserved for the tyrant.
21 Terrors sound in his ears;
In time of peace the destroyer cometh upon him.
22 He believeth not in a return from darkness,
And he is selected for the sword.
23 He roameth about after bread: "Ah! where is it?"
He knoweth that a dark day is near at hand for him.
24 Trouble and anguish terrify him;
They seize him as a king ready to the battle.
All the days of the ungodly he (the ungodly) is sensible of pain. רשׁע stands, like Elohim in Genesis 9:6, by the closer definition; here however so, that this defining ends after the manner of a premiss, and is begun by הוּא after the manner of a conclusion. מתחולל, he writhes, i.e., suffers inward anxiety and distress in the midst of all outward appearance of happiness. Most expositors translate the next line: and throughout the number of the years, which are reserved to the tyrant. But (1) this parallel definition of time appended by waw makes the sense drawling; (2) the change of עריץ (oppressor, tyrant) for רשׁע leads one to expect a fresh affirmation, hence it is translated by the lxx: ἔτη δὲ ἀριθμητὰ δεδομένα δυνάστῃ. The predicate is, then, like Job 32:7, comp. Job 29:10; Job 2:4 (Ges. 148), per attractionem in the plur. instead of in the sing., and especially with מספּר followed by gen. plur.; this attraction is adopted by our author, Job 21:21; Job 38:21. The meaning is not, that numbered, i.e., few, years are secretly appointed to the tyrant, which must have been sh'nôth mispâr, a reversed position of the words, as Job 16:22; Numbers 9:20 (vid., Gesenius' Thes.); but a (limited, appointed) number of years is reserved to the tyrant (צפן as Job 24:1; Job 21:19, comp. טמן, Job 20:26; Mercerus: occulto decreto definiti), after the expiration of which his punishment begins. The thought expressed by the Targ., Syr., and Jerome would be suitable: and the number of the years (that he has to live unpunished) is hidden from the tyrant; but if this were the poet's meaning, he would have written שׁניו, and must have written מן־העריץ.
With regard to the following Job 15:21-24, it is doubtful whether only the evil-doer's anxiety of spirit is described in amplification of הוא מתחולל, or also how the terrible images from which he suffers in his conscience are realized, and how he at length helplessly succumbs to the destruction which his imagination had long foreboded. A satisfactory and decisive answer to this question is hardly possible; but considering that the real crisis is brought on by Eliphaz later, and fully described, it seems more probable that what has an objective tone in Job 15:21-24 is controlled by what has been affirmed respecting the evil conscience of the ungodly, and is to be understood accordingly. The sound of terrible things (startling dangers) rings in his ears; the devastator comes upon him (בוא seq. acc. as Job 20:22; Proverbs 28:22; comp. Isaiah 28:15) in the midst of his prosperity. He anticipates it ere it happens. From the darkness by which he feels himself menaced, he believes not (האמין seq. infin. as Psalm 27:13, לראות, of confident hope) to return; i.e., overwhelmed with a consciousness of his guilt, he cannot, in the presence of this darkness which threatens him, raise to the hope of rescue from it, and he is really - as his consciousness tells him - צפוּ (like עשׂוּ, Job 41:25; Ges. 75, rem. 5; Keri צפוי, which is omitted in our printed copies, contrary to the testimony of the Masora and the authority of correct MSS), spied out for, appointed to the sword, i.e., of God (Job 19:29; Isaiah 31:8), or decreed by God. In the midst of abundance he is harassed by the thought of becoming poor; he wanders about in search of bread, anxiously looking out and asking where? (abrupt, like הנה, Job 9:19), i.e., where is any to be found, whence can I obtain it? The lxx translates contrary to the connection, and with a strange misunderstanding of the passage: κατατέτακται δὲ δἰς σῖτα γυψίν (איּה לחם, food for the vulture). He sees himself in the mirror of the future thus reduced to beggary; he knows that a day of darkness stands in readiness (נכון, like Job 18:12), is at his hand, i.e., close upon him (בּידו, elsewhere in this sense ליד, Psalm 140:6; 1-Samuel 19:3, and על־ידי, Job 1:14).
In accordance with the previous exposition, we shall now interpret וּמצוּקה צר, Job 15:24, not of need and distress, but subjectively of fear and oppression. They come upon him suddenly and irresistibly; it seizes or overpowers him (תּתקפהוּ with neutral subject; an unknown something, a dismal power) as a king עתיד לכּידור. lxx ὥσπερ στρατηγὸς πρωτοστάτης πίπτων, like a leader falling in the first line of the battle, which is an imaginary interpretation of the text. The translation of the Targum also, sicut regem qui paratus est ad scabellum (to serve the conqueror as a footstool), furnishes no explanation. Another Targum translation (in Nachmani and elsewhere) is: sicut rex qui paratus est circumdare se legionibus. According to this, כידור comes from כּדר, to surround, be round (comp. כּתר, whence כּתר, Assyr. cudar, κίδαρις, perhaps also הזר, Syr. חדר, whence chedor, a circle, round about); and it is assumed, that as כּדּוּר signifies a ball (not only in Talmudic, but also in Isaiah 22:18, which is to be translated: rolling he rolleth thee into a ball, a ball in a spacious land), so כּידור, a round encampment, an army encamped in a circle, synon. of מעגּל. In the first signification the word certainly furnishes no suitable sense in connection with עתיד; but one may, with Kimchi, suppose that כידור, like the Italian torniamento, denotes the circle as well as the tournament, or the round of conflict, i.e., the conflict which moves round about, like tumult of battle, which last is a suitable meaning here. The same appropriate meaning is attained, however, if the root is taken, like the Arabic kdr, in the signification turbidum esse (comp. קדר, Job 6:16), which is adopted of misfortunes as troubled experiences of life (according to which Schultens translates: destinatus est ad turbulentissimas fortunas, beginning a new thought with עתיד, which is not possible, since כמלך by itself is no complete figure), and may perhaps also be referred to the tumult of battle, tumultus bellici conturbatio (Rosenm.); or of, with Fleischer, one starts from another turn of the idea of the root, viz., to be compressed, solid, thick, which is a more certain way gives the meaning of a dense crowd.
(Note: The Arab. verb kdr belongs to the root kd, to smite, thrust, quatere, percutere, tundere, trudere; a root that has many branches. It is I. transitive cadara (fut. jacduru, inf. cadr) - by the non-adoption of which from the original lexicons our lexicographers have deprived the whole etymological development of its groundwork - in the signification to pour, hurl down, pour out, e.g., cadara-l-ma, he has spilt, poured out, thrown down the water; hence in the medial VII. form incadara intransitive, to fall, fall down, chiefly of water and other fluids, as of the rain which pours down from heaven, of a cascade, and the like; then improperly of a bird of prey which shoots down from the air upon its prey (e.g., in the poetry in Beidhwi on Sur. 81, 2: "The hawk saw some bustards on the plain f'ancadara, and rushed down"); of a hostile host which rushes upon the enemy first possible signification for כידור]; of a man, horse, etc., which runs very swiftly, effuse currit, effuso curru ruit; of the stars that shall fall from heaven at the last day (Sur. 81, 2). Then also II. intransitive cadara (fut. jacdiru) with the secondary form cadira (fut. jacdaru) and cadura (fut. jacduru), prop. to be shaken and jolted; then also of fluid things, mixed and mingled, made turgid, unclean, i.e., by shaking, jolting, stirring, etc., with the dregs (the cudre or cudde); then gen. turbidum, non limpidum (opp. Arab. ṣf'), with a similar transition of meaning to that in turbare (comp. deturbare) and the German trben (comp. traben or trappen, treiben, treffen). The primary meaning of the root takes another III. turn in the derived adjectives cudur, cudurr, cundur, cundir, compressed, solid, thick; the last word with us (Germans) forms a transition from cadir, cadr, cadr, dull, slimy, yeasty, etc., inasmuch as we speak of dickes Bier (thick beer), etc., cerevisia spissa, de la bire paisse. Here the point of contact of the word כידור, tumult of battle, κλόνος ἀνδρῶν, seems indicated: a dense crowd and tumult, where one is close upon another; as also נלחם, מלחמה, signify not reciprocal destruction, slaughter, but to press firmly and closely upon one another, a dense crowd. - Fl.)
Since, therefore, a suitable meaning is obtained in two ways, the natural conjecture, which is commended by Proverbs 6:11, עתיד לכּידון, paratus ad hastam = peritus hastae (Hupf.), according to Job 3:8) where ערר = לערר), may be abandoned. The signification circuitus has the most support, according to which Saadia and Parchon also explain, and we have preferred to translate round of battle rather than tumult of conflict; Jerome's translation, qui praeparatur ad praelium, seems also to be gained in the same manner.

Pain - Lives a life of care, and fear, and grief, by reason of God's wrath, the torments of his own mind, and his outward calamities. Hidden - He knows not how short the time of his life is, and therefore lives in continual fear of losing it. Oppressor - To the wicked man: he names this one sort of them, because he supposed Job to be guilty of this sin, in opposition of what Job had affirmed of the safety of such persons, Job 12:6, and because such are apt to promise themselves a longer and happier life than other men.