John Calvin Commentary Isaiah 24:13

"For thus shall it be in the midst of the earth among the peoples, as the shaking of an olive-tree, as the gleanings when the vintage is done." — Isaiah 24:13 (ASV)

For it shall be in the midst of the land. Since this statement is inserted between the threats and the consolation, the Prophet appears to address the chosen people, and not all the nations indiscriminately; unless we should rather say that he describes the dispersion by which the Jews were divided, as it were, into many nations. But this being a harsh and forced interpretation, I interpret it to mean simply that some hope is left for the ruined nations; and certainly, this prediction applies strictly to the kingdom of Christ, and therefore we need not wonder that some part of salvation is also promised to the Gentiles.

As the shaking of an olive-tree. The Prophet has elsewhere used the same metaphor, but it was when he spoke of the Church alone (Isaiah 17:5–6). On that occasion he said that some seed of God would be left, so that believers might not think that the Church was utterly ruined. For when "the olives are shaken," a few olives are still left, and some grapes after the vintage. In the same way, after the terrible destruction that will fall upon the Church, a small number of the godly will be left.

But now he extends the same promise to other parts of the world, as they were to become partakers of the same grace through Christ. Yet there is still a mixture of threat, as if he had said that the earth will be deprived of its inhabitants in exactly the same manner as the trees and vines are stripped of their fruits.