Is he the God of the Jews only? is he not also of the Gentiles? Yes, of the Gentiles also:
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Ambrosiaster
AD 400
Undoubtedly there is only one God for everybody. For even the Jews cannot claim that their God is not the God of the Gentiles also, because they believe that the origin of all people is from the one Adam and that no one who comes willingly to the law may be prevented from accepting it. Some Gentiles actually went with the Israelites into the desert of Egypt, and the Israelites were ordered to accept them as long as they agreed to be circumcised and eat unleavened bread, or the Passover, together with the rest of them. Then again Cornelius, a Gentile who was not judaized, received the gift of God, and it is clear from holy Scripture that he was justified. Commentary on Paul’s Epistles.