John Calvin Commentary Acts 11:1

"Now the apostles and the brethren that were in Judaea heard that the Gentiles also had received the word of God." — Acts 11:1 (ASV)

And the apostles. While Luke declares that the report of one household that was converted was spread everywhere among the brethren, this arose out of amazement; for the Jews regarded it as something monstrous that the Gentiles should be gathered to them, as if they had heard that men had been made from stones.

Again, the excessive love for their nation hindered them from acknowledging the work of God. For we see that the Church was troubled through this ambition and pride, because the equality, which diminished their dignity, was not tolerable. For this reason, they contended stoutly to bring the necks of the Gentiles under the yoke.

But since it was foretold in so many prophecies of the prophets that the Church should be gathered from all peoples after the Messiah's coming, and since Christ had commanded his apostles concerning the preaching of the gospel throughout the whole world, how can it be that the conversion of a few men should affect some as a strange thing, and terrify others as if it were something monstrous?

I answer that whatever was foretold concerning the calling of the Gentiles was understood as though the Gentiles would be made subject to the Law of Moses so that they might have a place in the Church. But the manner of the calling, the beginning of which they then saw, was not only unknown but also seemed to be entirely contrary to reason.

For they imagined that it was impossible for the Gentiles to be mixed with the sons of Abraham and be made one body with them (with the ceremonies taken away) without great injury being done to the covenant of God. For to what end did the Law serve, except to be the dividing wall to mark the separation?

Secondly, because they had been familiar with that difference their entire lives, the unexpected newness of the situation so struck them that they forgot everything that should have calmed their minds. Finally, they did not immediately comprehend the mystery, which, as Paul teaches, was unknown to the angels from the creation of the world.