John Calvin Commentary Isaiah 37:32

"For out of Jerusalem shall go forth a remnant, and out of mount Zion they that shall escape. The zeal of Jehovah of hosts will perform this." — Isaiah 37:32 (ASV)

For out of Jerusalem shall go forth a remnant. Previously, by the metaphor of a root and of fruits, he had foretold the deliverance of the Church; he now declares the same thing without figurative language. He alludes to the siege in which a small number of people, who had been left in the city, were shut up as in a prison and reduced to great hardship; he says that they will now go out, and that the whole country will be open to them, and that they will be free to move wherever they wish without fear.

The going forth is in this way contrasted with the narrow limits within which the trembling Jews had been forced by the fear of enemies to confine themselves. Yet with this word he expresses not only freedom to go out, but also the increase of the nation, which had been reduced to a small number.

When not only was Judea again covered by a multitude of people, but from that remnant also sprang vast multitudes who were spread over the various countries of the world, this could not have happened unless the Lord, out of that small number, had created not merely a single nation but many nations.

The zeal of Jehovah of hosts will do this. Not only does he contrast “the zeal of God” with the purposes of men, in order to praise the excellence of the work, but he also states that it is sufficient for every purpose, allowing God to provide an astonishing demonstration of His power. At first glance, as we have said, this seemed incredible; there were obstacles on every side, and no source of help. Therefore, he declares that God regards His Church with such fervent love that He does not hesitate to work in an extraordinary way to promote her salvation. The same type of expression was used by him on a similar occasion (Isaiah 9:7).