Who knoweth, the power of thy anger? Moses again returns to speak of the peculiar afflictions of the Israelites; for he had also on this occasion complained before of the common frailty and miseries of mankind. He justly exclaims that the power of God's wrath is immeasurably great. So long as God withholds his hand, men wantonly leap about like runaway slaves, who are no longer afraid at the sight of their master; nor can their rebellious nature be reduced to obedience in any other way than by his striking them with the fear of his judgment. The meaning then is, that whilst God hides himself, and, so to speak, dissembles his displeasure, men are inflated with pride, and rush upon sin with reckless impetuosity; but when they are compelled to feel how dreadful his wrath is, they forget their loftiness, and are reduced to nothing. What follows, According to thy fear, so is thy wrath, is commonly explained as denoting that the more a man is inspired with reverence towards God, the more severely and sternly is he commonly dealt with; for "judgment begins at the house of God," (1-Peter 4:17.) Whilst he pampers the reprobate with the good things of this life, he wastes his chosen ones with continual troubles; and in short, "whom he loveth he chasteneth," (Hebrews 12:6.) It is then a true and profitable doctrine that he deals more roughly with those who serve him than with the reprobate. But Moses, I think, has here a different meaning, which is, that it is a holy awe of God, and that alone, which makes us truly and deeply feel his anger. We see that the reprobate, although they are severely punished, only chafe upon the bit, or kick against God, or become exasperated, or are stupified, as if they were hardened against all calamities; so far are they from being subdued. And though they are full of trouble, and cry aloud, yet the Divine anger does not so penetrate their hearts as to abate their pride and fierceness. The minds of the godly alone are wounded with the wrath of God; nor do they wait for his thunderbolts, to which the reprobate hold out their hard and iron necks, but they tremble the very moment when God moves only his little finger. This I consider to be the true meaning of the prophet. He had said that the human mind could not sufficiently comprehend the dreadfulness of the Divine wrath. And we see how, although God shakes heaven and earth, many notwithstanding, like the giants of old, treat this with derision, and are actuated by such brutish arrogance, that they despise him when he brandishes his bolts. But as the Psalmist is treating of a doctrine which properly belongs to true believers, he affirms that they have a strongly sensitive feeling of the wrath of God which makes them quietly submit themselves to his authority. Although to the wicked their own conscience is a tormentor which does not suffer them to enjoy repose, yet so far is this secret dread from teaching them to humble themselves, that it excites them to clamor against God with increasing frowardness. In short, the faithful alone are sensible of God's wrath; and being subdued by it, they acknowledge that they are nothing, and with true humility devote themselves wholly to Him. This is wisdom to which the reprobate cannot attain, because they cannot lay aside the pride with which they are inflated. They are not touched with the feeling of God's wrath, because they do not stand in awe of him.

Who knoweth the power of thine anger? - Who can measure it, or take a correct estimate of it, as it is manifest in cutting down the race of people? If the removal of people by death is to be traced to thine anger - or is, in any proper sense, an expression of thy wrath - who can measure it, or understand it? The cutting down of whole generations of people - of nations - of hundreds of million of human beings - of the great, the powerful, the mighty, as well as the weak and the feeble, is an amazing exhibition of the "power" - of the might - of God; and who is there that can fully understand this? Who can estimate fully the wrath of God, if this is to be regarded as an expression of it? Who can comprehend what this is? Who can tell, after such an exhibition, what may be in reserve, or what further and more fearful displays of wrath there may yet be?
Even according to thy fear, so is thy wrath - literally, "And according to thy fear, thy wrath." The word rendered "fear" would here seem to refer to the "reverence" due to God, or to what there is in his character to inspire awe: to wit, his power, his majesty, his greatness; and the sense seems to be that his wrath or anger as manifested in cutting down the race seems to be commensurate with all in God that is vast, wonderful, incomprehensible. As no one can understand or take in the one, so no one can understand or take in the other. God is great in all things; great in himself; great in his power in cutting down the race; great in the expressions of his displeasure.

Who knoweth the power of thine angers - The afflictions of this life are not to be compared to the miseries which await them who live and die without being reconciled to God, and saved from their sins.

(k) Who knoweth the power of thine anger? even according to thy fear, [so is] thy wrath.
(k) If man's life for the shortness of it is miserable, it is even more so if your wrath is on it, as they who fear you only know.

Who knoweth the power of thine anger?.... Expressed in his judgments on men: as the drowning of the old world, the burning of Sodom and Gomorrah, the consumption of the Israelites in the wilderness; or in shortening the days of men, and bringing them to the dust of death; or by inflicting punishment on men after death; they are few that take notice of this, and consider it well, or look into the causes of it, the sins of men: such as are in hell experimentally know it; but men on earth, very few closely attend to it, or rarely think of it:
even according to thy fear, so is thy wrath; or who knows thy wrath, so as to fear thee? who considers it so, as that it has such an influence upon him to fear the Lord, and stand in awe of him, and fear to offend him, and seek to please him? or rather the wrath of God is answerable to men's fear of him; and that, in some things and cases, men's fears exceed the things feared; as afflictions viewed beforehand, and death itself: the fears of them are oftentimes greater, and more distressing, than they themselves, when they come; but so it is not with the wrath of God; the greatest fears, and the most dreadful apprehensions of it, do not come up to it; it is full as great as they fear it is, and more so.

The whole verse may be read as a question implying the negative, "No one knows what Thy anger can do, and what Thy wrath is, estimated by a true piety."

Thy fear - According to the fear of thee; according to that fear which sinful men have of a just God. So - It bears full proportion to it, nay indeed doth far exceed it.