... It is clear to me that "the born again" metaphor follows directly from a "transcendence of self" experience which some call "epiphany". I think it is too general to be identified with Christianity specifically.
Keep in mind, Jesus was speaking as member of the Jewish tradition--one with a universal approach. What we call "Christianity" came later, under the leadership of Paul.
Acts 11:19-26 (New Living Translation)
The Church in Antioch of Syria
19 Meanwhile, the believers who had been scattered during the persecution after Stephen’s death traveled as far as Phoenicia, Cyprus, and Antioch of Syria. They preached the word of God, but only to Jews. 20 However, some of the believers who went to Antioch from Cyprus and Cyrene began preaching to the Gentiles[a] about the Lord Jesus. 21 The power of the Lord was with them, and a large number of these Gentiles believed and turned to the Lord.
22 When the church at Jerusalem heard what had happened, they sent Barnabas to Antioch. 23 When he arrived and saw this evidence of God’s blessing, he was filled with joy, and he encouraged the believers to stay true to the Lord. 24 Barnabas was a good man, full of the Holy Spirit and strong in faith. And many people were brought to the Lord.
25 Then Barnabas went on to Tarsus to look for Saul. 26 When he found him, he brought him back to Antioch. Both of them stayed there with the church for a full year, teaching large crowds of people. (It was at Antioch that the believers[b] were first called Christians.)
Footnotes:
1. Acts 11:20 Greek the Hellenists (i.e., those who speak Greek); other manuscripts read the Greeks.
2. Acts 11:26 Greek disciples; also in 11:29.
