John Calvin Commentary Matthew 10:5

"These twelve Jesus sent forth, and charged them, saying, Go not into [any] way of the Gentiles, and enter not into any city of the Samaritans:" — Matthew 10:5 (ASV)

Into the way of the Gentiles. This makes even more evident what I have recently hinted: that the office then given to the apostles had no other purpose than to awaken in the Jews the hope of an approaching salvation, and thus to make them more attentive to hear Christ.

For this reason, he now confines their voice within the limits of Judea, which he later commands to sound everywhere, to the furthest limits of the world. The reason for this initial confinement is that he had been sent by the Father to be the minister of circumcision, to fulfill the promises which had long ago been given to the fathers (Romans 15:8).

Now, God had entered into a special covenant with the family of Abraham, and therefore Christ acted properly in confining the grace of God, at the outset, to the chosen people, until the time for publishing it had fully come. But after his resurrection, he spread over all nations the blessing which had been promised in the second place, because then the veil of the temple had been rent, (Matthew 27:51) and the middle wall of partition had been thrown down, (Ephesians 2:14). If anyone imagines that this prohibition is unkind because Christ does not admit the Gentiles to the enjoyment of the gospel, let him contend with God, who, to the exclusion of the rest of the world, established his covenant with the seed of Abraham alone—the covenant on which the command of Christ is founded.