How then comfort ye me in vain - That is, how can you be qualified to give me consolation in my trials, who have such erroneous views of the government and dealings of God? True consolation could be founded only on correct views of the divine government; but such views, Job says, they had not. With their conceptions of the divine administration, they could not administer to him any real consolation. We may learn hence,
(1) That all real consolation in trial must be based on correct apprehensions of the divine character and plans. Falsehood, delusion, error, can give no permanent comfort.
(2) They whose office it is to administer consolation to the afflicted, should seek after the "truth" about God and his government.
They should endeavor to learn why he afflicts people, what purpose he proposes to accomplish, and what are the proper ends of trial. They should have an unwavering conviction that he is right, and should see as far as possible "why" he is right, before they attempt to comfort others. Their own souls should be imbued with the fullest conviction that all the ways of God are holy, and then they should go and endeavor to pour their convictions into other hearts, and make them feel so too. A minister of the gospel, who has unsettled, erroneous, or false views of the character and government of God, is poorly qualified for his station, and will be a "miserable comforter" to those who are in trial. Truth alone sustains the soul in affliction. Truth only can inspire confidence in God. Truth only can break the force of sorrow, and enable the sufferer to look up to God and to heaven with confidence and joy.
(The end of Part One of the Commentary on Job)

How then comfort ye me in vain - Mr. Good translates: "How vainly then would ye make me retract!" See the note on Job 21:2. I cannot retract any thing I have said, as I have proved by fact and testimony that your positions are false and unfounded. Your pretensions to comfort me are as hollow as the arguments you bring in support of your exceptionable doctrines.
This chapter may be called Job's triumph over the insinuated calumnies, and specious but false doctrines, of his opponents. The irritability of his temper no longer appears: from the time he got that glorious discovery of his Redeemer, and the Joyous hope of an eternal inheritance, Job 19:25, etc., we find no more murmurings, nor unsanctified complainings. He is now full master of himself; and reasons conclusively, because he reasons coolly. Impassioned transports no longer carry him away: his mind is serene; his heart, fixed; his hope, steady; and his faith, strong. Zophar the Naamathite is now, in his presence, as an infant in the gripe of a mighty giant. Another of these pretended friends but real enemies comes forward to renew the attack with virulent invective, malevolent insinuation, and unsupported assertion. Him, Job meets, and vanquishes by pious resignation and fervent prayer. Though, at different times after this, Job had his buffetings from his grand adversary, and some seasons of comparative darkness, yet his faith is unshaken, and he stands as a beaten anvil to the stroke. He effectually exculpates himself, and vindicates the dispensations of his Maker.
There appears to be something in the Job 21:29 which requires to be farther examined: Have ye not asked them that go by the way? And do ye not know their tokens? It is probable that this verse may allude to the custom of burying the dead by the way-side, and raising up specious and descriptive monuments over them. Job argues that the lot of outward prosperity fell alike to the just and to the unjust, and that the sepulchral monuments by the wayside were proofs of his assertion; for his friends, as well as himself and others, had noted them, and asked the history of such and such persons, from the nearest inhabitants of the place; and the answers, in a great variety of cases, had been: "That monument points out the place where a wicked man lies, who was all his lifetime in prosperity and affluence, yet oppressed the poor, and shut up the bowels of his compassion against the destitute; and this belongs to a man who lived only to serve his God, and to do good to man according to his power, yet had not a day of health, nor an hour of prosperity; God having given to the former his portion in this life, and reserved the recompense of the latter to a future state."
The Septuagint render the verse thus: - Ερωτησατε παραπορευμενους ὁδον, και τα σημεια αυτων ουκ απαλλοτριωσατε, "Inquire of those who pass by the way, and their signs [monuments] ye will not alienate." That is, When ye hear the history of these persons, ye will not then assert that the man who lived in prosperity was a genuine worshipper of the true God, and therefore was blessed with temporal good, and that he who lived in adversity was an enemy to God and was consequently cursed with the want of secular blessings. Of the former ye will hear a different account from those who dare now speak the truth, because the prosperous oppressor is no more; And of the latter ye shall learn that, though afflicted, destitute, and distressed, he was one of those who acknowledged God in all his ways, and never performed an act of religious service to him in hope of secular gain; sought his approbation only, and met death cheerfully, in the hope of being eternally with the Lord.
Neither good nor evil can be known by the occurrences of this life. Every thing argues the certainty of a future state, and the necessity of a day of judgment. They who are in the habit of marking casualties, especially if those whom they love not are the subjects of them, as tokens of Divine displeasure, only show an ignorance of God's dispensations, and a malevolence of mind that would fain arm itself with the celestial thunders, in order to transfix those whom they deem their enemies.

How then comfort (u) ye me in vain, seeing in your answers there remaineth falsehood?
(u) Saying that the just in this world have prosperity and the wicked adversity.

How then comfort ye me in vain,.... This is the conclusion Job draws from the above observations: his friends came to comfort him, and they took methods for it, as they thought, but miserable comforters were they all; what they administered for comfort was in vain, and to no purpose; nor could any be expected from them, on the plan upon which they proceeded; they suggested he was a bad man, because of his afflictions, and they exhorted him to repentance and reformation, and then promised him happiness and prosperity upon it; which could not be expected, as appeared from the face of things in Providence; since, according to the above instances and proofs, wicked men enjoy prosperity, and good men had usually a great share of adversity:
seeing in your answers there remaineth falsehood; all their replies to Job were filled with these intimations and suggestions, that wicked men were only and always afflicted; or if they were at any time in prosperity, it was but for a little while; that good men were seldom or never afflicted, at least as Job was, or but a little afflicted, and for a little while: now Job had proved the contrary to all this, and therefore no consolation could be hoped for from men that held such tenets; comfort only springs from truth, and not falsehood; a man that speaks the truths, or delivers out the truths of God's word, he speaks to comfort and edification; but he that brings nothing but error and falsehood can never be the means and instrument of true solid comfort to any. Job having thus fully proved his point, and confuted the notions of his friends, it might have been thought they would have sat down in silence, and made no further answer; but Eliphaz rises up a third time, and makes a reply, as follows.

falsehood--literally, "transgression." Your boasted "consolations" (Job 15:11) are contradicted by facts ("vain"); they therefore only betray your evil intent ("wickedness") against me.

How - Why then do you seek to comfort me with vain hopes of recovering my prosperity, seeing your grounds are false, and experience shews, that good men are often in great tribulation, while the vilest of men prosper.