1 Now a certain man, a Pharisee named Nicodemus, who was a member of the Jewish ruling council, 2 came to Jesus at night and said to him, “Rabbi, we know that you are a teacher who has come from God. For no one could perform the miraculous signs that you do unless God is with him.” 3 Jesus replied, “I tell you the solemn truth, unless a person is born from above, he cannot see the kingdom of God.” 4 Nicodemus said to him, “How can a man be born when he is old? He cannot enter his mother’s womb and be born a second time, can he?” 5 Jesus answered, “I tell you the solemn truth, unless a person is born of water and spirit, he cannot enter the kingdom of God. 6 What is born of the flesh is flesh, and what is born of the Spirit is spirit. 7 Do not be amazed that I said to you, ‘You must all be born from above.’
Yevamot 62aBabylonian Talmud
§ It was stated that amora’im disagreed over the following issue: If a man had children when he was a gentile and he subsequently converted, Rabbi Yoḥanan said: He has already fulfilled the mitzva to be fruitful and multiply, and Reish Lakish said: He has not fulfilled the mitzva to be fruitful and multiply. Rabbi Yoḥanan said he has fulfilled the mitzva to be fruitful and multiply, as he already had children. And Reish Lakish said he has not fulfilled the mitzva to be fruitful and multiply, as the legal status of a convert who just converted is like that of a child just born, and it is considered as though he did not have children.
Notes and References
"... Greek gennethe anothen is sometimes rendered "born again" and sometimes "born from above"; my rendering reflects my conclusion that both aspects are relevant; also see 1 Peter 1:3-4. While the widespread currency since the 1970's of the expression "born-again Christian" originates here, the concept itself is Jewish, as demonstrated by this example from the Talmud: 'Shim'on Ben-Lakish said, "...a proselyte is like a newborn infant'"(Yevamot 62a); likewise Rabbi Yosi (Yevamot 48b). The idea resembles that of the 'new creation' (2C 5:17), which too is found in rabbinic literature (e.g., in Genesis Rabbah 39:11) ..."
Stern, David H. Jewish New Testament Commentary (p. 165) Jewish New Testament Publications, 1994