Baptism is the essential perquisite for both admission into the church and salvation in the Christian faith. It can be effected either by physical immersion or, in the case of this being impossible on account of water not be available, by desire
or if a person is of a different religious confession (or an atheist), by implicit desire in spirit, according to Catholic doctrine.
A type of baptism first emerged as a rite of purification for admission into the new Israel, in the renewal movement led by a prophet who preceded Jesus called John
the Baptist (of course).
Josephus describes John as "
one who exhorted the Jews to practice virtue and act with justice toward one another and with piety toward God, and so to gather together by baptism" (
Josephus, Ant. 18.117; cf. Luke 3:10-14). John was calling his Jewish audience to gather together into a new religious group, and baptism was the means by which the group was gathered.
The Baptist movement was an offshoot of Second Temple Judaism. John taught his disciples to pray in a certain way, fast and baptise. His baptism was an adaption of
Tvilah, a Jewish purification ritual of immersing in water, which is required for, among other things,
conversion to Judaism, but differs from Christian baptism in being a repeatable phenomenon and isn't as important to Judaism as, say, circumcision.
John made baptism the central ritual of his eschatological sect. Of John the Baptist Professor E.P. Sanders (
Jesus and Judaism) writes:
That John himself was an eschatological prophet of repentance is clearly implied in Josephus’s account. Further, the depiction of John and his message in the Gospels agrees with Josephus’s view: the preaching in the desert; the dress, which recalled Elijah; the message of repentance in preparation for the coming judgment. These features correctly pass unquestioned in New Testament scholarship... [Josephus] writes that Herod had him executed because he feared that trouble would result. Baptism and piety do not account for that reaction, and a message of national redemption is thus made probable (p. 92)
John's baptism functioned as an alternative to the temple sacrifices commended as the central rite of Judaism in the Torah and by the first century Sadducees. Thyen thus describes John's baptism as "
a polemic substitute for temple-sacrifice." Kraeling (John the Baptist, 15-27) attributes John's wilderness existence to "
some bitter experience" (p. 16) that, as a rural priest, had alienated him from the temple establishment.
Jesus was originally, according to a consensus of scholars, a close disciple of John and underwent baptism at his hands by full-body immersion in the river Jordan. In other words, Jesus was one of the people 'gathered' into the new movement. Prior to being baptized, Jesus had lived the life of a peasant carpenter in the Galilean town of Nazareth. Something drew him south to the Jordan to join John's new community. And this was the turning point of his life, encouraging him to start his ministry.
After John's death, Jesus was recognised by some Baptists as the greater figure John had prophesied, whereas a smaller group refused to recognise him as the successor and went into schism. This group existed contemporaneously with the early church, as can be seen from the Book of Acts references to those who "
knew only the baptism of John", but soon died out and lingers on today only in the Mandaean community of Gnostics (the Sabeans, as Muslims call them).
The texts that describe John's expected figure (Mark 1:7-8; Matt 3:11-12 = Luke 3:16-17) include the following elements: (1) his activities include judgement and restoration of Israel; (2) he is coming; (3) he is mightier than John (4) he will baptize with holy spirit and fire, as opposed to just water like John, and (5) his judgement and restoration are portrayed using imagery of a threshing floor, which implies gathering 'wheat' (the righteous) and eliminating chaff (the wicked).
The subsequent Christian baptism was distinct from the Johannine baptism in two ways: firstly, like John predicted, Christ taught that the most important aspect of baptism was not just the outer washing (although this was essential) but the inner purification brought on by the Holy Spirit, which accompanied Jesus's water immersion, and therefore (essentially) made all who were baptised in his name 'prophets', no longer consigned to a special class favoured by God to share his message with the world.
Secondly, Jesus's baptism was not intended only for Jews like its Jewish and Baptist precursors. It was open to everyone, Jew or Gentile, therefore becoming the universal admission rite of a properly universal creed.