11 And he received the sign of circumcision, a seal of the righteousness of the faith which he had while still uncircumcised, that he might be the father of all those who believe, though they are uncircumcised, that righteousness might be imputed to them also, 12 and the father of circumcision to those who not only are of the circumcision, but who also walk in the steps of the faith which our father Abraham had while still uncircumcised. (Romans 4:11–12, NKJV)
God commanded circumcision of Abraham as a “sign of the covenant” He made with him (Gen. 17:1-14, esp. 10-11). The apostle calls attention to that historic moment. Like a seal marking authenticity, Abraham’s circumcision served as a sign or indicator “of the righteousness of the faith which he had” while still uncircumcised. This distinction is notable and confirms the blessings of Abraham are offered to all (Jews and Gentiles). It also confirms that faith is the means of justification, not the works of the law of Moses (Rom. 4:13). Verse 12 says Abraham is the father of those who “walk in the steps of the faith” he had before circumcision. Walking is active. Thus, faith is active – it involves steps. Faith obeys God, just like father Abraham. He did not earn the blessings of the covenant through keeping law. He was sinner, saved “by grace, through faith” (Rom. 4:1-5). His (obedient) faith expressed his trust in God, and his faith was accounted to him for righteousness. Obedient faith is the only kind of faith that saves us (Jas. 2:17, 20-24).