Christian baptism, which has the form of a ceremonial washing . .
. is a sign from God that signifies inward cleansing and remission
of sins, … Spirit-wrought regeneration and new life, and the
abiding presence of the Holy Spirit as God’s seal testifying and
guaranteeing that one will be kept safe in Christ forever… .
Baptism carries these meanings because first and fundamentally it
signifies union with Christ in his death, burial, and resurrection[,] .
. . and this union with Christ is the source of every element in our
salvation. 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