Baptism is the sign of someone being a Christian. It represents the washing away of a person’s sins by the Spirit and the beginning of a new life in Jesus Christ.
There are lots of differences of understanding regarding baptism within the Christian church. Those in the Protestant Reformed tradition (and others) do not see the water of baptism as having any power in and of itself. Rather, it functions as a sign and seal of rebirth only when it accompanies the reality which it signifies. That is, baptism is a sign and seal of regeneration only when accompanied by faith on the part of the one being baptised, since faith in Christ is evidence of regeneration.
So far, it might seem to make most sense if Christians in the Reformed tradition would baptise only professing believers. But probably most Christians in the Reformed tradition have also baptised the infants of believers. Why is that?
Having listened to a few talks recently on the subject, the argument seems to be based on the continuity between the Old Covenant and the New Covenant. In the Old Covenant, the (male) children of Abraham are given the sign of circumcision, which is the sign of admission into the Old Covenant community. In the New Covenant, since God hasn’t become less merciful, the children of believers are similarly to be included in the New Covenant community. So it is appropriate for the (male and female) children of believers to receive the sign of admission into the New Covenant community.
The problem I have with this is that it doesn’t seem to take into account the different ways in which the Abrahamic covenant is present in the Old Covenant and New Covenant eras.
In the Old Covenant era, the Abrahamic covenant is present in promise and anticipation. The male descendants of Abraham are circumcised as a sign and seal of the promise made to Abraham based on Abraham’s faith (Romans 4:11), that God will bless him with many descendants, and that God will establish his covenant between himself and Abraham and Abraham’s offspring (Genesis 17:1-14). Circumcision looks ahead to the fulfilment of the promise. It is a sign of something that is not yet a reality.
In the New Covenant era, the Abrahamic covenant is present in fulfilment and reality. God has established his covenant with Abraham’s offspring, Jesus the Christ. Those who share in the faith of their spiritual father Abraham (Romans 4:12) receive through Christ the promised inheritance as they are washed by the renewal of the Spirit (Galatians 3:14; Titus 3:5), and as they receive the circumcision of the heart (Romans 2:28-29; Colossians 2:11-12). Baptism is therefore the sign that the promise sealed and anticipated in the sign of circumcision has now been fulfilled in the gift of the Spirit to a believer. It is the sign of something that is a present reality.
Those who baptise unregenerated infants make baptism into a sign of promise and anticipation, rather than a sign of a present reality. In contrast, the New Testament always speaks of baptism as a sign of a present reality. For example, Paul writes, “In him also you were circumcised with a circumcision made without hands, by putting off the body of the flesh, by the circumcision of Christ, having been buried with him in baptism, in which you were also raised with him through faith in the powerful working of God, who raised him from the dead” (Colossians 2:11-12, ESV, emphasis added). I can’t imagine Paul writing that to a church where a sizeable number of those present had been baptised but hadn’t put their faith in Christ.
The best illustration I can think of is the difference between an engagement ring and a wedding ring. The engagement ring is the sign of a promise made and is an anticipation of a future reality. The wedding ring is a sign of a present reality, as it is given as the sign and seal of the vows that have already been made. It is appropriate for (some) unmarried people to wear an engagement ring, but it is not appropriate for any unmarried people to wear a wedding ring. Similarly, it is appropriate for (some) unregenerated people to receive the sign of circumcision, but it is not appropriate for any unregenerated people to receive the sign of baptism.
Having said all that, what if the profession of faith is made after the sign of baptism is received? For example, what if someone is baptised as a baby, and many years later professes faith? Should the sign of baptism be readministered? Baptists have traditionally said that it should be, and not only on the basis of the mode of baptism (immersion versus sprinkling or pouring). But maybe there’s room for some greater flexibility on the question of re-baptism?