John Calvin Commentary Psalms 149:9

"To execute upon them the judgment written: This honor have all his saints. Praise ye Jehovah." — Psalms 149:9 (ASV)

To perform the judgment, etc. He qualifies what he had said in the previous verses, in which he might have appeared to arm the Lord’s people for deeds of warlike cruelty. At first sight, it might appear strange that those who were called the merciful ones of God should be sent out with drawn swords to commit slaughter and pour out human blood; for what evidence was here of mercy?

But when God himself is the author of the vengeance taken, it is just judgment, not cruelty. When mention is made of the judgment written, the Psalmist reminds the Jews that they were called to liberty by command of God—to that liberty which had been unjustly wrested from them by foreigners and tyrants, and that they could not be blamed for executing judgment written.

Any exposition of the passage is faulty if it does not proceed from this as the Psalmist’s design: that he would have the Jews consider the divine mandate, not act under the influence of private resentment, and rein in their passion. He was, in effect, saying that God’s children may not execute vengeance except when called to it, since all moderation ends when people yield to the impulse of their own spirits.

Another question might arise here by way of objection. Christ is said to have come without crying or lifting up his voice, so that he might not break the bruised reed (Matthew 12:20), and he inculcates the same character upon his followers. The answer is obvious: Christ is also armed with an iron scepter, with which to bruise the rebellious, and is elsewhere described as stained with blood, slaying his enemies on every side, and not being wearied with their slaughter (Isaiah 63:2).

Nor is it surprising, considering the obstinacy that universally prevails in the world, that the mercy which is treated with such indignity should be converted into severity.

Now, the doctrine laid down in the passage can be rightly applied to our practice in this way: what is said here of the two-edged sword applies especially to the Jews, and not properly to us, who are not permitted such power. An exception, indeed, is that rulers and magistrates are vested by God with the sword to punish all kinds of violence; but this is something peculiar to their office.

As for the Church collective, the sword now put into our hand is of another kind—that of the word and Spirit—so that we may slay for a sacrifice to God those who formerly were enemies, or else deliver them over to everlasting destruction unless they repent (Ephesians 6:17). For what Isaiah predicted of Christ extends to all who are his members,—

“He shall smite the wicked with the word of his mouth,
and shall slay them with the breath of his lips.”
(Isaiah 11:4).

If believers quietly confine themselves within these limits of their calling, they will find that the promise of vengeance on their enemies has not been given in vain. For when God calls us, as I have said above, to judgment written, he puts a restraint both on our spirits and actions, so that we must not attempt what he has not commanded.

When it is said, at the end of the verse, that this honor is to all the merciful ones of God, he not only exhorts to the practice of piety but also gives us a support for our encouragement, lest we think that we might be losers by exercising mercy and patience—as most people give vent to fury and rage, under the idea that the only way to defend their life is by showing the savagery of wolves.

Although God’s people, therefore, have none of the strength of the giant, and will not move a finger without divine permission, and have a calm spirit, the Psalmist declares that they have an honorable and splendid outcome from all their troubles.