YOU still don't see the "if" in Romans 4:2.
Rom 4:2
If Abraham was justified[fn] by works, he has something to brag about — but not before God.[fn]
That is about the WORK OF CIRCUMCISION.
JUST read HOW many times circumcision is mentioned in Romans!
Paul is NOT saying Abraham was not justified for obeying!
Romans 2:25
Circumcision has value if you observe the law, but if you break the law, you have become as though you had not been
circumcised.
Romans 2:27 The one who is not
circumcised physically and yet obeys the law will condemn you who, even though you have the written code and circumcision, are a lawbreaker.
Romans 2:28 A person is not a Jew who is one only outwardly, nor is
circumcision merely outward and physical.
Romans 2:29 No, a person is a Jew who is one inwardly; and
circumcision is circumcision of the heart, by the Spirit, not by the written code. Such a person’s praise is not from other people, but from God.
Romans 3:1 [ God’s Faithfulness ] What advantage, then, is there in being a Jew, or what value is there in
circumcision?
Romans 4:11 And he received
circumcision as a sign, a seal of the righteousness that he had by faith while he was still
uncircumcised. So then, he is the father of all who believe but have not been
circumcised, in order that righteousness might be credited to them.
Did you read that last scripture?
Paul speaks about Abraham receiving CIRCUMCISION as a sign, a seal that he had by faith. The work Paul was speaking about is the WORK of CIRCUMCISION.
Rom 4:3
For what does the Scripture say?
Abraham believed God,
and it was credited to him for righteousness.
Abraham believed BEFORE he did anything !
Maybe you should take a reading comprehension course !
You are the one with the problem.