John Calvin Commentary Isaiah 11:12

"And he will set up an ensign for the nations, and will assemble the outcasts of Israel, and gather together the dispersed of Judah from the four corners of the earth." — Isaiah 11:12 (ASV)

And he will lift up an ensign to the nations. This verse contains nothing more than the explanation of the previous verse. The language is metaphorical and can be understood in two ways: either that, by giving an ensign, he will terrify adversaries, so that they will not dare to prevent his people from returning; or that he will give an ensign to the wretched exiles so they do not hesitate to prepare for their return.

Even today, this doctrine is very useful for us. For just as an ensign is lifted up in the army so that the soldiers may gather, and that each one may follow and keep his proper place, so a banner is here held out to us so that we may gather to it—namely, the gospel, which the Lord has lifted up among the Gentiles, by which Christ is preached to us.

And will gather together the dispersions of Judah. Therefore, we should conclude that we cannot be gathered by the Lord unless we gather to this ensign and are joined to him by faith. For there is no other way in which he acknowledges us to be his sheep than when, after having been scattered, we are gathered together and meet in the same assembly under this ensign, as he says,

My sheep hear my voice and follow me (John 10:27).

The word gather is repeated. He will gather together the outcasts of Israel, and will gather together the dispersions of Judah. He shows how efficacious God’s calling will be, for as soon as he gives the slightest indication that such is his pleasure, he will restore the people. Dispersion is a collective noun, for it means the Jews scattered in all directions; and he appears to allude, as he often does elsewhere, to similar passages in the writings of Moses, where the Lord promises that he will gather the people, even if they were scattered to the farthest parts of the world and to the four winds of heaven (Deuteronomy 30:3–4).

Now, this was done under the direction of Christ. Under the same leader, we should today expect the restoration of a wretched and scattered Church, for there is no hope of gathering the remnant except by the elect looking to this ensign. Therefore, we should frequently remember those promises, so that by relying on them we may increasingly strengthen our hearts.