Here are thoughts on baptism by J.I. Packer:
THIS RITE EXHIBITS UNION WITH CHRIST by J. I. Packer
Or don’t you know that all of us who were baptized into Christ Jesus were baptized into his death? We were therefore buried with him through baptism into death in order that, just as Christ was raised from the dead through the glory of the Father, we too may live a new life. ROMANS 6:3-4
Christian baptism, which has the form of a ceremonial washing (like John’s pre-Christian baptism), is a sign from God that signifies inward cleansing and remission of sins (Acts 22:16; 1 Cor. 6:11; Eph. 5:25-27), Spirit-wrought regeneration and new life (Titus 3:5), and the abiding presence of the Holy Spirit as God’s seal testifying and guaranteeing that one will be kept safe in Christ forever (1 Cor. 12:13; Eph. 1:13-14). Baptism carries these meanings because first and fundamentally it signifies union with Christ in his death, burial, and resurrection (Rom. 6:3-7; Col. 2:11-12); and this union with Christ is the source of every element in our salvation (1 John 5:11-12). Receiving the sign in faith assures the persons baptized that God’s gift of new life in Christ is freely given to them. At the same time, it commits them to live henceforth in a new way as committed disciples of Jesus. Baptism signifies a watershed point in a human life because it signifies a new-creational engrafting into Christ’s risen life.
Christ instructed his disciples to baptize in the name of the Father, the Son, and the Holy Spirit (Matt. 28:19). This means that the covenant relation which baptism formally confers is one of acceptance by, communion with, and commitment to all three Persons of the Godhead. When Paul says that the Israelites were “baptized into Moses” (1 Cor. 10:2), he means that they were put under Moses’ control and direction. Thus, baptism into the name of the triune God signifies control and direction by God himself.
The outward sign does not automatically or magically convey the inward blessings that it signifies, and the candidates’ professions of faith are not always genuine. Peter had to tell the newly baptized Simon Magus that he was still unrenewed in heart (Acts 8:13-24).
As a sign of a once-for-all event, baptism should be administered to a person only once. Baptism is real and valid if water and the triune name are used, even if it is of an adult whose profession turns out to have been hypocritical. Simon Magus received baptism once, and if he came to real faith later it would have been incorrect to baptize him again.
No prescription of a particular mode of baptism can be found in the New Testament. The command to baptize may be fulfilled by immersion, dipping, or sprinkling; all three modes satisfy the meaning of the Greek verb baptizo and the symbolic requirement of passing under, and emerging from, cleansing water.
To baptize believers’ babies, in the belief that this accords with God’s revealed will, has been the historic practice of most churches. However, the worldwide baptist community, which includes distinguished Reformed thinkers, disputes it.
This links up with the baptist insistence that membership of local congregations is only for those who have publicly professed personal faith: an emphasis often buttressed by the claim that Christ instituted baptism primarily for a public profession of faith, and that such a profession is part of the definition of baptism, so that infant baptism is not really baptism at all. (Therefore baptist churches usually rebaptize as believers persons baptized in infancy who have come to faith; from the baptist standpoint they are still unbaptized.) Reformed theology negates the view that believer-baptism is the only baptism and rejects baptist denials of a place for believers’ children in the body of Christ by virtue of their parentage, and thus from birth. These differences about the visible church form the background for all discussions of infant baptism as such.
The case for baptizing believers’ infants (a practice that the New Testament neither illustrates nor prescribes nor forbids) rests on the claim that the transition from the “old” to the “new” form of God’s covenant that was brought about by the coming of Christ did not affect the principle of family solidarity in the covenant community (i.e., the church, as it is now called). Infants were therefore to be baptized, as Jewish male infants had previously been circumcised, not to confer on them covenant status, but to attest the covenant status that by God’s sovereign appointment their parentage had already given them.
In 1 Corinthians 7:14, Paul resolves the question of whether God accepts a marriage in which only one partner has become a Christian by invoking the certainty that the children of such a marriage are relationally and covenantally “holy,” that is, are dedicated to and accepted by God in company with their one Christian parent. So the principle of parent-and-child solidarity still stands, as Peter also indicated in his Pentecost sermon (Acts 2:39). But if infants share covenant status with their parent, it is fitting, other things being equal, to give them the sign of that status and of their place in the covenant community, and it would be unfitting for the church to withhold it. This fitness is demonstrated by the fact that when circumcision was the sign of covenant status and community inclusion, God commanded it explicitly (Gen. 17:9-14).
Against this, baptists affirm that (a) circumcision was primarily a sign of Jewish ethnic identity, so the parallel alleged between it and Christian baptism is a mistake; (b) under the new covenant, the requirement of personal faith before baptism is absolute; and (c) practices that Scripture does not explicitly recognize and approve must not be brought into church life.
Certainly, all adult church members should have professed faith personally before the church, and communities that baptize infants provide for this in a rite of confirmation or its equivalent. The Christian nurture of baptist and paedobaptist children will be similar: dedicated to God in infancy, either by baptism or by a dedication rite (which some will see as a dry baptism), they will then be brought up to live for the Lord and led to the point of publicly professing faith on their own account in confirmation or baptism (which some will see as a wet confirmation). After this they will enjoy full communicant status, unless indeed they come under discipline for some lapse. The ongoing debate is not about nurture but about God’s way of defining the church.
From: Concise Theology: A Guide To Historic Christian Beliefs