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.
— J. I. Packer