One only has to read the Great Commission to see that Jesus commands baptism for his followers. The call was to ‘go into all the world and make disciples of all nations, baptising them in the name of the Father, and the Son, and the Holy Spirit’ (Matthew 28:19). As we read through Acts, we see the apostles continuing to baptise, linking baptism directly to the call to repentance (cf. Acts 2:38).
Many are quite happy with Jesus’ call to baptism in principle. Far more people take issue with the linking of baptism and membership. Some object to the principle that baptism ought to precede membership. Others take issue with the idea that baptism marks our entrance into the church. They wish to separate out baptism from membership, seeing them as distinct acts. I want to suggest here that biblically and historically baptism was understood to be your entrance to membership. As a consequence, refusing to join in membership with the church is a basis for denying baptism.
Most people are happy enough assenting to the view that baptism symbolises our union with Christ (cf. Gal 3:27). ‘Putting on Christ’ signifies receiving Christ, being in Christ and becoming one with Christ. Paul links this to our union with Jesus in his work of redemption; being joined to his death (cf. Rom 6:1-5), linked to his resurrection (cf. Col 2:11f; 2 Cor 5:17) and anticipating future glory with him (cf. Col 3:1-4).
However, if baptism signifies our union with Christ, it must also mark our union with his people, the church. The bible is clear that to be ‘in Christ’ is to be united with his people. Paul notes in Galatians 3:26-28:
26 for in Christ Jesus you are all sons of God, through faith. 27 For as many of you as were baptised into Christ have put on Christ. 28 There is neither Jew nor Greek, there is neither slave nor free, there is no male and female, for you are all one in Christ Jesus.
Similarly, Paul states in 1 Corinthians 12:12-13:
12 For just as the body is one and has many members, and all the members of the body, though many, are one body, so it is with Christ.13 For in one Spirit we were all baptised into one body—Jews or Greeks, slaves or free—and all were made to drink of one Spirit.
Notice particularly what he says in v13: ‘we were all baptised into one body’. Our baptism brings us into the body of Christ. We are brought into the covenant by faith in Christ and we are brought into the body through baptism, which is our identification with Jesus and his people.
It is worth comparing this to Acts 2:41:
So those who received his word were baptised, and there were added that day about three thousand souls.
Two things seem pertinent here. First, as the vast majority of churches throughout history acknowledge – whether paedobaptist, credobaptist or dual practice – baptism precedes membership. However, in baptist polity particularly, 41a is not divorced from 41b and 41c. Not only does baptism precede membership but the entire order is significant: receipt of the word (that is, coming to faith) precedes baptism which, in turn, precedes membership. However, for the purposes of our discussion here, it is significant only to note that baptism precedes membership.
Second, given the earlier passages that suggest baptism marks entrance to the church, there is a direct linking of faith, baptism and being added to their number. Mike Gilbart-Smith notes:
Just as faith-producing Spirit baptism is the door to membership of the invisible body of Christ, so public water baptism is the door to the visible church.
Christians across the centuries have recognised this. The question of “whom should we baptise” was identical to the question “whom should we admit to church membership”. So, when Thomas Shepard argues for infant baptism in seventeenth century New England, he entitles his treatise, “The Church Membership of Children.”
The distinction between baptism and membership (and similarly communion) is a relatively recent one. As Jonathan Leeman has rightly said, ‘Baptism and the Lord’s Supper are just signs of the thing. Church membership is the thing itself’. George Beasley-Murray rightly notes, ‘to be baptised to Christ is to be baptised to his Body. And to be accepted by Christ into his church, but not by the local church into which he is baptised, would be preposterous’. Again, Gilbart-Smith puts it helpfully:
Just as the marriage service and marital intercourse are signs of the marriage, so baptism and the Lord’s Supper are signs of church membership. Baptism without church membership is like getting married and returning to the parental home (without your spouse!)
The point, then, is that baptism marks your entrance to the visible church. Biblically, baptism marks your union with Christ which, simultaneously, signifies your union with his people. Historically, the church has understood baptism to mark entrance to the church. Those who trusted Christ were baptised and thus admitted to church membership upon their baptism. There was no separation between baptism and membership; the one entailed the other. Baptism was your entrance to membership of the church.
What does this mean in practice for those who wish to be baptised but who will not join the church in membership? We can read that view as stating the following: I want to identify with Christ and his people through the one-time event of baptism but I don’t want to identify with Christ and his people in the ongoing event of membership. Both signify the same thing. Thus, an unwillingness to join the church is tantamount to an unwillingness to identify with Christ and his people. This means that a stated desire not to join the church is a stated desire not to identify with Christ and his people in an ongoing way. When understood this way, how can we baptise somebody who will not join the church in membership?
 See 1 Cor 12:13, Acts 2:41
 Shepard, T., “The Church Membership of Children” in I. H. Murray, The Reformation of the Church (Edinburgh: Banner of Truth, 1965) 383-409.
 For a more fulsome discussion about restricted communion, see my articles ‘four reasons I would restrict communion to members’ and ‘Communion, individualism and your relationship with God’
 Beasley-Murray, G., “A Baptist interpretation of the place of the child in the church” in Foundations 8 (April 1965) 157-158.