Baptism as Objective Seal
According to the Reformed position, baptism is a sign and seal of the covenant of grace. This puts it on a continuum with circumcision, which was given to Abraham and his children as “a seal of the righteousness of the faith…” (Romans 4:11). All three Reformed confessions describe baptism in this way. Receiving a seal upon yourself means something official and objective has happened. It is similar to a king putting his seal on an order to verify “these words are mine”. Or, in a less glorious example, a rancher putting the brand of his ranch on his cattle. God ordained the sign of circumcision to visibly mark out His people under the old covenant, and in Christ the bloody sign of circumcision has been transfigured into the cleansing sign of baptism. The Belgic confession describes this very well, pointing out that Christ, by His sacrifice, put an end to all shedding of blood, including the requirement of circumcision. In its place, to mark out His people, He instituted baptism (Belgic Confession, Article 34, para. 1 & 2). Colossians 2:9-12 describes this as well. Our circumcision is now made without hands, because Christ has suffered the ultimate circumcision – His death on the cross. His people are now baptized in His name; physical circumcision is no longer required.
So then when we are baptized, something objective and measurable changes. Just as with circumcision for Israel of old, baptism places us in a binding covenant with God. As the words of institution of baptism indicate, after our baptism we bear the name of the Trinity, because those are the names we are baptized into. The Belgic Confession states of baptism: “By it we are received into God’s church and set apart from all other people and alien religions, that we may be dedicated entirely to him, bearing his mark and sign. It also witnesses to us that he will be our God forever, since he is our gracious Father.” (Article 32, para. 2) Just as other people can look at our baptism and know we are God’s people, we also can look at our own baptism and know we are in covenant with God. This provides us with both a moral imperative (to obey the master we belong to) and the comfort of knowing we belong to a gracious God. As the objective seal of God’s covenant, baptism is our initiation into His covenant people, the church.