John Calvin Commentary Isaiah 41:15

"Behold, I have made thee [to be] a new sharp threshing instrument having teeth; thou shalt thresh the mountains, and beat them small, and shalt make the hills as chaff." — Isaiah 41:15 (ASV)

Lo, I have made thee. The Prophet still speaks of the restoration of the Church, and promises that she will be so victorious over her enemies as to crush and reduce them to powder; and he declares this by a highly appropriate metaphor. The Jews, whom he addresses, were nearly crushed, but he declares that, on the contrary, they shall crush their enemies, so that, after having been delivered, they shall render to them what had been done to themselves.

This needed to be added, for if they had not regained new strength, they would always have been exposed to the unlawful passions of their enemies. Therefore, they needed God to give them strength to repel the attacks made upon them. Yet Isaiah at the same time declares that they shall be executioners of the vengeance of God.

But it may be thought that in this way he inflames the Jews to desire revenge. Now, this is quite contrary to the nature of the Spirit of God. And, while we are too much inclined to this disease, the Lord is so far from showing forbearance toward these purposes of revenge that in many passages he commands us to repress them; for he exhorts us rather to pray for our enemies, and not to take delight in their distresses and afflictions (Matthew 5:44).

I reply, the Prophet here shows what will happen, but he neither commands nor exhorts us to desire the destruction of our enemies. If it is again objected that we ought not only to expect but even to desire what the Lord promises, when it tends to his glory and our salvation, I acknowledge that this consolation greatly tends to alleviate our sorrows when he promises that he will one day inflict punishment on enemies who have cruelly distressed us and will render to them the measure which they have meted out (Matthew 7:2).

Yet this is not inconsistent with God’s command that we should be kind-hearted. We should pity them because of the evils they bring upon themselves and bewail their wretched condition, instead of being led by cruel dispositions to rejoice in their destruction (Matthew 5:44).

If we embrace this promise with the faith we ought to cherish, we shall bring all the violence of the flesh into subjection. Consequently, we shall first be disposed to endure, and afterwards, with moderate zeal, shall desire God’s judgment.

Accordingly, our first aim ought to be to repress and lay aside every violent emotion of the flesh, and thus to await with an honest and sincere heart the appropriate time of divine judgment. This should not be so much from a concern for our private advantage, but so that due praise may be given to God’s justice. To the same purpose David wrote—

“The righteous shall rejoice when they shall see the vengeance;
they shall wash their feet in the blood of wicked men” (Psalms 58:10).

Not that they delight in their distresses, but because, as he afterwards adds, the righteous man receives his reward, and God’s righteous judgments are made known on earth when the wicked are punished for their transgressions.

The Jews, being by nature cruel and eager for bloodshed, seize on these promises like wild and savage beasts, which eagerly devour the prey offered to them and, as soon as they smell it, are mad with rage.

But the Lord does not wish his people to forget that kindness which he recommends above all things. For we cannot be his if we are not guided by the same spirit—that is, by the spirit of mildness and gentleness.

In a word, by this metaphor of “a harrow having teeth,” he means nothing other than the wretched destruction of the wicked, whom the Lord will put to flight by the hand of the godly; and this is for the purpose of comforting the godly, not of inflaming them with an eagerness for shedding blood.