Baptism
Baptism (Greek baptisma, from baptizein, "to dip, immerse, plunge") is the initiatory water rite of the Christian church, by which a person is washed in the name of the Father, the Son, and the Holy Spirit and visibly joined to Christ and his people. Commanded by the risen Christ in the Great Commission (Matthew 28:19) and practiced from the Day of Pentecost onward (Acts 2:38, 41), it stands alongside the Lord's Supper as one of the two sacraments (or ordinances) instituted by Jesus and received by every branch of the historic church.
Its roots lie in the ceremonial washings of the Old Covenant, where water signified cleansing from defilement (Leviticus 16:4; Numbers 19:17–19) and the prophets foresaw a coming purification of heart: "I will sprinkle clean water on you, and you shall be clean" (Ezekiel 36:25–27; cf. Zechariah 13:1). This hope took new form in John the Baptist, whose "baptism of repentance for the forgiveness of sins" (Mark 1:4; Luke 3:3) prepared Israel for the Messiah. Jesus himself, though sinless, was baptized in the Jordan River, where the Spirit descended as a dove and the Father's voice affirmed him (Matthew 3:13–17) — identifying with sinners and inaugurating his ministry. He spoke too of his death as a "baptism" to be undergone (Luke 12:50; Mark 10:38), the deeper reality the water foreshadows.
The apostolic church baptized believers immediately upon their reception of the word (Acts 8:12, 36–38; Acts 16:15, 33), binding the rite to repentance, faith, the forgiveness of sins, and the gift of the Holy Spirit (Acts 2:38). Paul gives baptism its richest theology: it unites the believer with Christ in his death, burial, and resurrection, so that the old self is buried and a new life begins — "we were buried therefore with him by baptism into death, in order that... we too might walk in newness of life" (Romans 6:3–4; Colossians 2:12). By one Spirit all are baptized into one body (1 Corinthians 12:13), having "put on Christ" as a garment (Galatians 3:27). Peter calls it an "appeal to God for a good conscience" that saves "through the resurrection of Jesus Christ" (1 Peter 3:21), and the new birth of water and Spirit (John 3:5; Titus 3:5) is closely tied to it.
Baptism's significance, therefore, is gospel made visible: it proclaims that salvation comes not by human effort but by being joined to the crucified and risen Lord. There is "one Lord, one faith, one baptism" (Ephesians 4:5), so the rite also marks the unity of the whole church. Christian traditions have long differed over its mode (immersion, pouring, or sprinkling), its subjects (professing believers only, or also the infant children of believers, by analogy with circumcision as the covenant sign), and the precise manner in which grace is conveyed. Yet all confess one baptism, administered once, in the triune name, as the appointed door of entrance into the visible people of God.