Jewish Baptism

Jewish proselyte baptism was an act following circumcision. Say a proselyte of 15 years of age wanted to become a Jew he would first be circumcised and then later he was baptized. It was at baptism they were considered a part of the Jewish people.

1. Circumcision did not make you part of the nation in and of itself.

2. Jews born physically into the nation were circumcised at 8 days. Then all who had become unclean had to undergo a Mikveh (immersion) to be considered clean again.  This was often after a sacrifice was made. The sacrifice and offering only covered one offense. All subsequent offenses required a new offering and a new immersion.

3. Proselytes were circumcised, met with Rabbis for teaching and  taught basic parts of the covenant, and then baptized(immersed) into the nation and covenant.

One of the problems of Catholic theory is that it reasons some are born into the Christian covenant, when in reality all are considered proselytes. Jesus clarified this in several locations. Especially John 3:1-6.

Joh 3:5  Jesus answered, “Truly, truly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God. 

Like a Jewish Mikveh, baptism is after sin and confesses the need for cleansing. Unlike Jewish mikveh, Christian baptism only occurs once. We can see glimpses of the mikveh in the New Testament as Jews cleansed or purified themselves as they were coming into Jerusalem for the passover or other feasts.

All Christians must be born again, there are none who are naturally born into the Christian nation after sinning. This is the reason Catholics and Protestants ere concerning Circumcision and Baptism. They believed Circumcision was replaced by baptism. The truth is, they were always two different things. The Jews considered circumcision and the immersion two different things, and could be days apart.

see

https://sermons.faithlife.com/sermons/37029-jewish-proselyte-baptism

There was process through which a non-Jew could become a Jewish proselyte, and that process involved three things. A sacrifice, circumcision, and baptism. The sacrifice was a heifer or a pair of turtledoves. It was brought to the priest and given as a burnt offering to God.

This would correspond to Christ's sacrifice, God bringing one to faith, and then baptism.

       The Mikveh which was a ceremonial bath used to bring the unclean into a state of cleanliness so they could enter the Temple and worship, was the common practice throughout the Law of Moses. It could be used for several types of uncleanness. It was sufficient until the days of John the Baptist when God made the general use of Mikveh insufficient to cleanse sin. The Pharisees basically believed the Law was entirely sufficient and saw no need for John's baptism. They also denied their need for cleansing. This is where they parted with God.

      Matthew 21 has a good debate between Christ and the rulers concerning the rejection of John's baptism. 

Mat 21:25  The baptism of John, R3from where did it come? R4From heaven or from man?” And they discussed it among themselves, saying, “If we say, ‘From heaven,’ he will say to us, R5‘Why then did you not believe him?’ 

Christ showed that a prophet could overshadow the existing law and require something more. John as a prophet sent by God acted by God's authority. His baptism was completely necessary and no general cleansing by animal sacrifice or mikveh washing could cleanse without John's baptism. 

Even their prayers were useless as long as they rejected John's words.

 Likewise Jesus after his resurrection required more than Jewish law. The Jewish law was systematically abolished.

Christian baptism was required to be "in (upon) the name of Jesus Christ", which means the common Mikveh was not sufficient to relieve uncleanness from sin. It was not upon Christ's name. Also, those baptized in Christ's name would no longer need the lesser Mikveh of the Law. Christ's sacrifice and baptism was once and for all times sufficient to enter the New Covenant temple, which was spiritual and heavenly. Those of the Catholic council of Nicea who said women in their period cycle must be segregated, simply said the death of Christ did not cleanse all uncleanness. It was a false concept reverting to the law.