“…since God is one—who will justify the circumcised by faith and the uncircumcised through faith.”
Since God is one, all humanity created by him is one. No one is superior to him. And since all are sinners, the way of salvation can only be one way. It’s either do or done.
Either we can do enough to earn God’s favor or it needs to be done for us. Either we can work for our salvation or it has to be a free gift by grace.
If it’s by grace, as Paul argues, it must then be for everyone in the world. Since God is one. Both Jew and Gentile now have the opportunity of eternal life!
It’s reason to praise God forever!