How forcible are right words! - How weighty and impressive are words of truth! Job means that he was accustomed to feel their power, and to admit it on his soul. If their words were such, he would listen to them with profound attention, and in silence. The expression has a proverbial cast.
But what doth your arguing reprove? - Or rather, what doth the reproof from you reprove? or what do your reproaches prove? Job professes a readiness to listen to words of truth and wisdom; he complains that the language of reproach used by them was not adapted to instruct his understanding or to benefit his heart. As it was, he did not feel himself convinced, and was likely to derive no advantage from what they said.

How forcible are right words - A well-constructed argument, that has truth for its basis, is irresistible.
But what doth your arguing reprove? - Your reasoning is defective, because your premises are false; and your conclusions prove nothing, because of the falsity of the premises whence they are drawn. The last clause, literally rendered, is, What reproof, in a reproof from you? As you have proved no fault you have consequently reproved no vice. Instead of מה נמרצו mah nimretsu, "how forcible," מה נמלצו mah nimletsu, "how savoury or pleasant," is the reading of two MSS., the Chaldee, and some of the rabbins. Both senses are good, but the common reading is to be preferred.

How (p) forcible are right words! but what doth your arguing reprove?
(p) He who has a good conscience does not shrink at the sharp words or reasonings of others, unless they are able to persuade him by reason.

How forcible are right words!.... That are according to right reason; such as may be called strong reasons, or bony arguments, as in Isaiah 41:21; there are strength and weight in such words, reasonings, and arguments; they bring evidence and conviction with them, and are very powerful to persuade the mind to an assent unto them, and have great influence to engage to a profession or practice of what they are used for; such are more especially the words of God, the Scriptures of truth, the doctrines of the Gospel; these are right words, see Proverbs 8:6; they are not contrary to right reason, although above it; and are agreeably to sanctified reason, and received by it; they are according to the perfections of God, even his righteousness and holiness, and according to the law of God, and in no wise repugnant to it, which is the rule of righteousness; and they are doctrines according to godliness, and are far from encouraging licentiousness; and they are all strictly true, and must be right: and there is a force and strength in those words; they come with weight, especially when they come in demonstration of the Spirit and power of God; they are mighty, through God, for the pulling down the strong holds of sin, Satan, and self, and for the bringing of men to the obedience of Christ; to the quickening dead sinners, enlightening dark minds, softening hard hearts; renewing, changing, and transforming men into quite another temper and disposition of mind they formerly had; for the comforting and relieving souls in distress, and saints under affliction; and have so very wonderful an influence on the lives and conversations of those to whom they come, not in word only, but in power and in the Holy Ghost, as to teach them to deny all sin and ungodliness, and to live soberly, righteously, and godly: or, "how forcible are the words of an upright man!" (a) that is, sincere, impartial, and faithful; which Job suggests his friends were not: some think Job has respect to his own words, and render the clause, "what hardness", or "harshness", have "right words!" (b) Such as he believed his own were, and in which there were nothing hard and harsh, sharp and severe, or which might give just offence; such as his cursing the day in which he was born, or charging his friends with treachery and deceit: but rather he tacitly reflects upon the words and arguments of his friends; intimating, that though there is force and strength in right words, theirs were neither right nor forcible, but partial and unjust, and weak and impotent; which had no strength of reasoning in them, nor carried any conviction with them, as follows:
but what doth your arguing reprove? their arguments they had used with him had no strength in them; they were of no avail; they did not reprove or convince of any evil he had been guilty of, or any mistake he had made; they were weak, impertinent, and useless, and fell with no weight upon him, nor wrought any conviction in him.
(a) So Aquila apud Drusium. (b) "quid duritiei habent verba rectitudinis", Schmidt; so Luther.

And what will your arguings reprove?--literally, "the reproofs which proceed from you"; the emphasis is on you; you may find fault, who are not in my situation [UMBREIT].

Forcible - The words of truth have a marvellous power. Reprove - But there is no truth in your assertions or weight in your arguments.