John Calvin Commentary Romans 10:12

"For there is no distinction between Jew and Greek: for the same [Lord] is Lord of all, and is rich unto all that call upon him:" — Romans 10:12 (ASV)

For there is no distinction, etc. Since faith alone is required, wherever it is found, there the goodness of God manifests itself for salvation. So, in this case, there is no difference between one people or nation and another. And he adds the strongest of reasons: for since He who is the Creator and Maker of the whole world is the God of all people, He will show Himself kind to all who will acknowledge and call on Him as their God. For as His mercy is infinite, it will surely extend itself to all who seek it.

Rich is to be understood here in an active sense, meaning kind and bountiful. And we may observe that the wealth of our Father is not diminished by His liberality, and that therefore it is not made less for us, with whatever multiplied affluence of His grace He may enrich others. So there is no reason why some should envy the blessings of others, as if they lost anything by it.

But though this reason is sufficiently strong, he further strengthens it with the testimony of the Prophet Joel, which, according to the general term used, includes all alike. Readers can see much more clearly from the context that what Joel declares harmonizes with the present subject. For in that passage, he prophesies about the kingdom of Christ. Furthermore, after saying that the wrath of God would burn in a dreadful manner, in the midst of His ardor, Joel promises salvation to all who would call on the name of the Lord. Hence, it follows that the grace of God penetrates into the abyss of death, if only it is sought there, so that it is by no means to be withheld from the Gentiles.