Genesis 17:11, 23 And ye shall circumcise the flesh of your foreskin; and it shall be a token of the covenant betwixt me and you. And Abraham took Ishmael his son, and all that were born in his house, and all that were bought with his money, every male among the men of Abraham’s house; and circumcised the flesh of their foreskin in the selfsame day, as God had said ubto him.
Abraham’s response of faith in God’s covenant promise called forth an immediate response of obedience. After the Lord made a covenant, then he gave a command: circumcise! The obedience of circumcision is the outward evidence of inward faith. Faith is defined in the NT as the ”circumcision of the heart.” Faith is not visible; circumcision, obedience, and good works are the visible fruit of faith. While ”faith is the evidence of things not seen,” obedience is the evidence of unseen faith.
Circumcision is a symbol of the circumcision of the flesh. Faith in Jesus is the crucifixion of the flesh, the renunciation of the devil, and the cutting off of the world. Circumcision was given by God as a ”token,” or a sign, of faith in grace. The OT believer remembered circumcision as a constant reminder of God’s Covenant of Grace. The NT believer remembers baptism as a constant reminder of Christ’s New Covenant of Grace. We need this reminder, because the devil, the world, and our own sinful flesh are ever and always at war with our renewed spirit. Immediate obedience arising out of faith is the right response. Remembering our baptism daily is our instant response.