We noted above on Colossians 2:11-12 that we do not see baptism replacing/fulfilling circumcision as the sign of the New Covenant, as it is often alleged by our paedobaptist brethren, but rather, circumcision of the foreskin has its counterpart in the circumcision of the heart. Circumcision of the foreskin was not fulfilled in water baptism, but rather in the circumcision of the heart. There is nothing said there about water baptism being fulfilled and has become the sign of the covenant, as it functioned for the Abrahamic Covenant. That was not the purpose or intention of the apostle. But we may indeed see baptism as a sign of the covenant because baptism signifies something. Our Confession says that baptism is “a sign of fellowship” and union with Christ, as we tried to show above. Baptism shows us the blessings of the covenant. In water baptism, we picture the spiritual union which we have in Christ and thus we have it as a sign of the blessings of the New Covenant. In baptism, we picture the death, burial, and resurrection of our Lord Christ and our union with Him. Therefore, baptism is a sign of the New Covenant.
The Lord’s Supper likewise functions as a sign of the New Covenant. A sign to be celebrated and not neglected, because, with the celebration of the Lord’s Supper, we remember the Lord’s death until He comes (1 Cor. 11:26). When we remember the Lord’s death in the Lord’s Supper, we have the gospel in visible form. We remember His great love for His own and the sacrifice of His life for our sake. We experience spiritual union with our Savior. We remember and express our thanksgiving for His great salvation and the forgiveness which he offered us on the cross and offers us daily. We celebrate His grace, in that he, God over all blessed forever (Rom. 9:5), became a man to take our sins upon Himself and give us His perfect righteousness.
We have two sovereign institutions given to us by the Mediator of the New Covenant, the Lord Christ, to function as visible manifestations of the truths of the gospel. They serve as visible signs and tokens to show inward ...