John Calvin Commentary Isaiah 31:8

"And the Assyrian shall fall by the sword, not of man; and the sword, not of men, shall devour him; and he shall flee from the sword, and his young men shall become subject to taskwork." — Isaiah 31:8 (ASV)

Then the Assyrian. The copulative ו (vau) is better translated as an adverb of time: “Then the Assyrian shall fall down.” That is, “When you shall have turned to the Lord, and when your life testifies to a sincere repentance, then the enemy shall fall down.” For, as the Lord raised up the Assyrian to punish the Jews for their crimes, and especially for idolatry, so He promises that the Assyrians shall be brought down when they shall have ceased to sin and worship idols.

Therefore, he informs us that our obstinacy is the reason why the Lord adds evil to evil, doubles His strokes, and pursues us more and more. For we continually supply fresh materials to inflame His vengeance against us more and more.

If, therefore, we wish that God’s chastisements should be less severe, and if we wish that our enemies should fall to the ground and perish, let us strive to be reconciled to Him by repentance. For He will speedily put an end to the chastisement and will take away from enemies the strength and power to injure us.

By the sword not of a man. The Prophet means that the deliverance of the Church is God’s own work, so that the Jews may know that, although no earthly power is visible, God’s secret power is sufficient to deliver them.

If, therefore, enemies are subdued, or if their rage is restrained, let us know that it proceeds from the Lord. Indeed, by various methods He represses the force and violence of wicked men, but by His own hand alone He delivers His Church.

For while the Lord makes use of human means, He preserves His own people miraculously and by extraordinary methods. These interventions can be seen throughout history, from the beginning of the world, and we may even now perceive them, if we are not blind. Yet this does not prevent the Lord from employing His servants to deliver the Church; He employs them in such a manner that His own hand is distinctively and gloriously displayed in it.

We know that this prediction of Isaiah was fulfilled when the Assyrian army was destroyed and Sennacherib was put to flight. For not by the arm of man was he destroyed; rather, the Lord displayed His power, so that it might be known that He alone is the deliverer of His Church (2 Kings 19:35; Isaiah 37:36).

By delivering Jerusalem at that time from the siege, God thus exhibited, as in a picture, spiritual redemption. He alone, therefore, will destroy our spiritual enemies. Consequently, it will be in vain for us to resort to other aids or remedies, or to rely on our own strength, which is nothing. Instead, let us seek the direction and assistance of God, and we will emerge victorious.

And his young men shall melt away. The Prophet means that the power of the Lord displayed against the Assyrians will be so great that the hearts of young men, who in other circumstances are usually fierce, will be completely softened and melt like wax. This is because young men, having less experience than older men, are for that reason more fierce and impetuous.

God will easily restrain such fierceness when He determines to deliver His people from the hands of their enemies. For this reason, Isaiah has especially mentioned “young men,” as if he had said, “the very flower or strength.”