The English word “baptism” is taken from the Greek word baptizo used in the New Testament to signify the ancient Hebrew ritual washing. The Hebrew word most commonly associated with the practice is mikveh, which means “a gathering of waters”.
The original idea in the Law of Moses was ritual cleansing. In particular, it was a remedy for ritual defilement. It was rather detailed regarding what kind of defilement and whether it was rainwater, a stream or spring water. The point was to restore one to the ritual purity necessary to enter the divine Presence. While the focus was on entering the Tabernacle/Temple, it included the concept that God was present among the Chosen, and ritual cleansing was necessary to restore covenant fellowship with the nation.
Once the Temple was built and standing in Jerusalem, ritual baths were built all around the city. It became a common practice for men to bathe on the way to the Temple out of an abundance of caution to wash away accidental defilement the worshiper might not know about.
Rather early in Israel’s history, the symbolism of the mikveh was associated with both the womb and the grave. These were the natural portals of human existence, beginning and end. Thus, the ritual washing symbolized a new life, with the implication of eternal life. It was restoring the primal relationship as a child of Jehovah, a rebirth. This was the teaching under the Law of Moses.
At the same time, there is no mention in the Old Testament of mikveh in relation to the ritual washing. The association of the term with ritual washing came rather late in the Second Temple period. After the Return and Restoration from Exile, Daniel’s prophecy of the timing of the Messiah was noted among rabbis. It was not so much a precise date, but in typical Hebrew fashion, was regarded as an approximation. Thus, about a century before Christ, the practice arose of using the mikveh to mark a repentance and turning to a life fit for the coming of the Messiah.
It was noted that Jeremiah used mikveh as the image of a fountain (Jeremiah 14:8, 17:13, 50:7) as the “hope of Israel”. Thus, the Messiah would be the ultimate mikveh of cleansing. This teaching was associated most clearly with the ministry of John the Baptist. He used the symbolic mikveh ritual as a way of marking preparation for the coming Passover Lamb of God. He will baptize in the fire of the Holy Spirit!
All of this was fresh in the minds of pious Jews during John’s ministry, through the ministry of Jesus, and in Peter’s preaching on the Day of Pentecost. In the minds of such Jews, it was the symbol of completing the Old Covenant and embracing the New. It was already in their minds that this ritual mikveh was departing from their old Jewish identity and moving forward into the Messianic Kingdom. It required understanding the Old in order to live in the New.
All the previous sweet sounding talk of the Nation being one people under the Covenant, one big family, was widely recognized as fake. Jesus was not proposing anything new in the Parable of the Good Samaritan; the ruling class of Jews were not one family with the people. And it was widely recognized that Samaritans at that time were quite conscientious about obeying a more primitive understanding of Moses. It was shocking only that Jesus would be so frank about what everyone knew all along. But when the first hundred or so disciples began actually living by the concept of adopting each other as the true family of the Messiah, it restored the real meaning of Covenant identity. It was something worthy of celebration.
This is why baptism became associated in Acts with people forming a fresh tribal identity, and merging their material assets into one single household. This is inherent in Paul’s teaching in Ephesians 1:10 about the “administration” or “dispensation” of the new age of the Messiah. Paul was explaining to a Hellenized audience in Ephesus the rich imagery of the old Hebrew prophecies about the Messiah. The merging of assets wasn’t required, but it was a natural voluntary response. This had a lot to do with the later event regarding Ananias and Sapphira. It represented the compassionate care of family folks.
Baptism is the mark of new life in the Messiah. It was purely symbolic, but an obligatory symbol to declare the new life in the household of the Messiah. What followed was the radical kind of obedience that made one alien to the rest of the world.
