John Calvin Commentary Romans 3:29

"Or is God [the God] of Jews only? is he not [the God] of Gentiles also? Yea, of Gentiles also:" — Romans 3:29 (ASV)

Is he the God of the Jews only? The second proposition is that this righteousness belongs no more to the Jews than to the Gentiles. And it was very important that this point should be urged, so that a free passage might be made for the kingdom of Christ throughout the whole world.

He does not, then, ask simply or expressly whether God was the Creator of the Gentiles, which was admitted without dispute, but whether He intended to reveal Himself as a Savior to them also.

Since He had put all mankind on the same level and brought them to the same condition, if there is any difference between them, it is from God, not from themselves, for they are all alike. But if it is true that God intends to make all the nations of the earth partakers of His mercy, then salvation—and righteousness, which is necessary for salvation—must be extended to all.

Therefore, under the name God, an intimation of a mutual relationship is conveyed, which is often mentioned in Scripture—

“I shall be to you a God, and you shall be to me a people.” (Jeremiah 30:22)

For the fact that God, for a time, chose for Himself a special people did not nullify the origin of mankind, who were all formed after the image of God and were to be nurtured in the world in the hope of a blessed eternity.