John Calvin Commentary Matthew 15:24

"But he answered and said, I was not sent but unto the lost sheep of the house of Israel." — Matthew 15:24 (ASV)

I am not sent. He informs the Apostles that his reason for refusing the woman of Canaan arises from his desire to devote himself entirely to the Jews, to whom alone he was appointed as a minister of the grace of God. He argues from the Father's call and command that he must not offer any assistance to strangers.

This was not because Christ's power was always confined within such narrow limits, but because present circumstances made it necessary for him to begin with the Jews and, at that time, devote himself to them in a special manner. For, as I have said in expounding Matthew 10:5, the middle wall of partition (Ephesians 2:14) was not thrown down until after Christ’s resurrection, so that he might proclaim peace to the nations that were aliens from the kingdom of God. Therefore, at that time, he prohibited the Apostles from scattering the first seed of doctrine anywhere but in Judea. Therefore, he rightly affirms that, on this occasion, he was sent only to the Jews, until the Gentiles also followed in the proper order.

To the lost sheep of the house of Israel. He bestows the designation sheep of the house of Israel not only on the elect, but on all who were descended from the holy fathers. For the Lord had included all in the covenant and was promised to all indiscriminately as a Redeemer, just as he also revealed and offered himself to all without exception. It is noteworthy that he declares himself to have been sent to LOST sheep, as he assures us in another passage that he came to save that which was lost (Matthew 18:11). Now as we enjoy this favor today, in common with the Jews, we learn what our condition is until he appears as our Savior.