What counts is a new creation!
Here Paul makes one final argument against those who are seeking to require the Christians of Galatia to keep certain customs of the Law, specifically circumcision. And it is the most persuasive one.
He simply says being circumcised or not being circumcised doesn’t really matter at all!
That’s because the only thing that really matters is whether one is being changed. A New Creation!
The Law of Moses, indeed any law or custom alone can never change a person’s heart and life. No human effort can produce a peaceful relationship with God. No amount of rule-keeping can provide a clean conscience before God.
Only Jesus can do these things for us.
This is why Paul says - May I never boast except in the cross of our Lord Jesus Christ, through which the world has been crucified to me, and I to the world.
The only way we can ever be in a right relationship with God is through Jesus. By His death on the cross, Jesus took the penalty for our sins and only by trusting what He accomplished will we ever find confidence before God.
It is the persistent tendency of religion to substitute imperfect human effort at rule-keeping for the perfect work of Jesus on the cross! So the apostle Paul says if you must have a rule, take this one - A New Creation!
By faith in Jesus’ death and resurrection we have forgiveness for all our failures in keeping God's rules. We are born again and set upon a path that leads to becoming more and more like Jesus in heart and life. This is the rule for students of Jesus.
Peace and mercy to all who follow this rule, even to the Israel of God.