“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” (Romans 4:11).
At the age of 99, Abraham, his son Ishmael, and all males born in his house and bought with his money were circumcised (Genesis 17:1, 23). It sealed the covenant God had made between the patriarch and Himself (Genesis 17:2), and it served as a seal of the righteousness which Abraham had had reckoned to him because of his faith (Genesis 15:6). For a Jew, circumcision was not intended to be a substitute for faith or obedience; rather, its purpose was to be a pledge of consecration to God. Like many things found in the Old Testament, circumcision was intended to foreshadow an equally momentous New Testament event.
Because Christ is the fulfillment of God’s seed promise to Abraham (Galatians 3:16), “in Christ Jesus neither circumcision nor uncircumcision avails anything” (Galatians 6:15); obedience does (1 Corinthians 7:19). The act of physical circumcision has no spiritual significance in the new covenant.
Of supreme significance in the New Testament is the spiritual circumcision God performs when you are baptized into Christ (Colossians 2:11-12). In a circumcision made without human hands, God cuts off the guilt of past sins when you are buried with Christ in baptism. Though dead in your trespasses, God makes you alive together with Christ, forgiven of all your sins (Colossians 2:13), saved through the washing of regeneration and renewing of the Holy Spirit (Titus 3:5). You are cut off from your past; you are washed, sanctified, and justified in the name of the Lord Jesus Christ and by the spirit of our God (1 Corinthians 6:11).
In baptism you are now made a partaker of a covenant God has made; it is the new covenant Jesus inaugurated with His own blood (Matthew 26:28). The one baptism is not a meaningless ritual, nor is it a substitute for a life of faith and obedience. It is a new birth (John 3:3, 5) in which you become a new creation. Old things have passed away; all things have become new (2 Corinthians 5:17) when you are circumcised spiritually “with the circumcision made without hands…the circumcision of Christ, buried with Him in baptism” (Colossians 2:11-12).