For neither circumcision counts for anything, nor uncircumcision, but a new creation. And as for all who walk by this rule, peace and mercy be upon them, and upon the Israel of God (Galatians 6:15-16).
When I first read this passage I thought it was a misprint because it said, "the Israel of God," because the Old Testament always referred to the Lord as "The God of Israel." Looking at the context, I realized that this is not a misprint, which leaves the question, what is the Israel of God? A better question would be, who is the Israel of God?
The book of Galatians was written to Christians who have allowed false teachers to come in their church and teach a false gospel which points back to their works rather than the grace of God. These men taught that faith in Christ is not enough, you must be circumcised and obey the Law. Paul used the entire letter to teller his readers that they are recipients of grace through faith in Jesus Christ not based on circumcision.
Paul said made reference to Abraham who trusted in God by faith was credited to him as righteousness and has stated that "those of faith who are the sons of Abraham" (Galatians 3:7). Those who are truly believers in Christ are "Abraham's offspring, heirs according to promise" (Galatians 3:29). Abraham was uncircumcised when he first believed showing that circumcision in not a necessity to come to faith in Jesus Christ. Paul in Galatians 6:15 says what counts is being a new creation in Christ, not any outward sign. This is good news for us because our works can never save us (Ephesians 2:8-9).
Who is the Israel of God? The Israel of God is the community of faith. That's right, the church. God's design for the church is to be one people saved by his grace through Jesus Christ for all nations. There is no dominate nation in the church, we are all one in Christ who rest in the grace of God.