By the time the gospel of Jesus Christ was introduced into history, the religion of the Jews had strayed far afield from God’s intention for it. Designed to be a spiritual tutor to bring the descendants of Abraham to Christ (Galatians 3:24), and then be removed when Christ’s new and better covenant replaced it (Jeremiah 31:31-34), it had been perverted into a grotesque synthesis of meritorious works via circumcision and legalism (i.e., adding the oral tradition of the doctrines and commandments of men to the all-sufficient law of Moses). The most noxious fruit on this hideous tare was the self-righteous boasting it generated–“I am not like other men…I fast twice a week; I give tithes of all that I possess” (Luke 18:11-12).
Because the gospel eradicated all boasting in human merit (Romans 3:27, 4:2), it stood apart from first century Judaism as the east does from the west.
The fourth chapter of Romans is purposeful and powerful in its systematic proof that Abraham was not justified by works of merit. Because “Abraham believed God, and it was accounted to him for righteousness” (Genesis 15:6) occurred after he had lied about his wife Sarai in Egypt (Genesis 12:10-20), it is indisputable that he was not justified because he was without sin. Therefore, he had not lived so perfectly that he had earned or merited the blessing of justification/righteousness.
Because “Abraham believed God, and it was accounted to him for righteousness” (Genesis 15:6) occurred at least fourteen years before God made the covenant of circumcision with him (cf. Genesis 12:4-5, 16:13, 17:1), it is indisputable that he was justified while uncircumcised. Therefore, circumcision was not the cause of justification in Abraham’s life, it was an effect.
Because “Abraham believed God, and it was accounted to him for righteousness” (Genesis 15:6) occurred centuries before the nation of Israel’s exodus from Egypt (Exodus 12:40) and the Law given to Moses at Mount Sinai, it is indisputable that Abraham was not justified by keeping the Law. Abraham’s reception of God’s promises of a land, a nation, and a seed did not come through the Law. Abraham lived and died justified in God’s sight without any knowledge of the Law. Therefore, the blessing of justification and being “the heir of the world was not to Abraham or to his seed through the law, but through the righteousness of faith” (Romans 4:13).
Abraham was not justified by works of merit, or by circumcision, or by the Law of Moses. He was justified by faith in the promised seed (i.e., Jesus—Galatians 3:16) whose gospel is the faith which was once for all delivered to the saints (Jude 3). Therefore, those who walk in the steps of the faith are sons of Abraham (Romans 4:11-12; Galatians 3:29).