Jesus explained to Nicodemus that this doctrine was in error—that every person must have two births—natural birth of the physical body and another of the water and the spirit.This discourse with Nicodemus established the Christian belief that all human beings—whether Jew or Gentile—must be "born again" of the spiritual seed of Christ.
This phrase (without the article), refers to a rebirth which the early Church regarded as taking place through baptism (1 Pet 1.3, 23; Tit 3.5)." The Catechism of the Catholic Church notes that the essential elements of Christian initiation are: "proclamation of the Word, acceptance of the Gospel entailing conversion, profession of faith, Baptism itself, and the outpouring of the Holy Spirit, and admission to Eucharistic communion" (CCC 1229).
In the sermon entitled A New Birth he writes, "none can be holy unless he be born again", and "except he be born again, none can be happy even in this world. a man should not be happy who is not holy." Also, "I say, [a man] may be born again and so become an heir of salvation." Wesley also states infants who are baptized are born again, but for adults it is different: The quotation from the Gospel of John has raised some questions about the meaning and authenticity of the phrase "born again".
In the chapter, Nicodemus is puzzled and asks Jesus what he means by saying that "Ye must be born again".
The Apostle Peter further reinforced this understanding in The Catholic Encyclopedia states that "[a] controversy existed in the primitive church over the interpretation of the expression the seed of Abraham.
It is [the Apostle Paul's] teaching in one instance that all who are Christ's by faith are Abraham's seed, and heirs according to promise.
Baptism gives the person the grace of forgiveness for all prior sins; it makes the newly baptized person a new creature and an adopted son of God (2 Corinthians ; 2 Peter 1:4); it incorporates them into the Body of Christ (Ephesians ) and creates a sacramental bond of unity leaving an indelible mark on our souls (CCC 1262-1274).