Summary: . Paul has already made it clear that there must be an inward change of heart and obedience to the law, and that mere external observances can never save a lost sinner. Now Paul proceeds to show how Abraham was pronounced righteous before he was circumc
THOUGHTS ABOUT THE PASSAGE:
The flesh is a built-in law of failure, making it impossible for the natural man to please or serve God. It is a compulsive inner force inherited from man’s fall, which expresses itself in general and specific rebellion against God and His righteousness. The flesh can never be reformed or improved. The only hope for escape from the law of the flesh is its total execution and replacement by a new life in the Lord Jesus Christ. (Mark Bubeck, The Adversary, Moody Press, p. 28.)
In the previous passages we have seen how the Jews boasted in circumcision and the law. Paul has already made it clear that there must be an inward change of heart and obedience to the law, and that mere external observances can never save a lost sinner.
Now Paul proceeds to show how Abraham was pronounced righteous before he was circumcised, on the basis of his faith alone. He does this by asking the Jews whether Abraham’s justification occurred before or after he was circumcised. Abraham’s age when he was declared righteous (Genesis 15:6 (quickview) ) is not stated. However, when Hagar bore Ishmael Abraham was 86 (Genesis 16:16 (quickview) ). It was not until he was 99 years old that he was circumcised (Genesis 17:23 (quickview)  27). This means that the circumcision of Abraham followed his justification by faith by more than 13 years.
Circumcision was an outward sign of the justification that Abraham had already received. Therefore both Jews and Gentiles must do more than be circumcised to be right with God. They must also walk in the footsteps of faith like Abraham did. Abraham was justified by believing God’s promise, and not by obeying God’s law; for God’s law had not been given as yet through Moses. The same is true today. God justifies the ungodly because they believe in His precious promise, and not because they obey the law. Those who are trying to work for their salvation often lean on two crutches:
1. Their own imagined goodness.
2. Some kind of religious observance.
Neither one of these things will help us to merit salvation. It is only in the finished work of Christ.
I know that I can never depend on my baptism, or church membership or good works to save me. This is what the Jews were doing with circumcision. The above things are only outward signs of the inward trust that took place when I gave my heart and life to Jesus Christ.