Regeneration (gennao anothen, “born again” or, “born from above”) is most clearly stated in John 1:12-13 and 3:3-8. While Nicodemus thinks Jesus is talking about a second birth (“He cannot enter a second time into his mother’s womb and be born, can he?” John 3:4, all quotations are from nasb), the alternate possible meaning of birth from above is better since the source of the birth of God that makes one a child of God is more important than the idea of simply being alive again. Perhaps best is to hold both ideas of enlivening spiritual renewal and birth from God (as the new source for one’s existence).
The language of having become a child of God (Jesus uses the analogy of physical birth) coincides with Pauline terms of new life, new creation, the new self, being in Christ, and life in the Spirit. By analogy with physical birth, spiritual birth and being made alive are stated as instantaneous, not as a lifelong process (cf. the instantaneous transfer in John 5:24 “he who hears My word, and believes in Him who sent Me, has eternal life, and does not come into judgment, but has passed out of death into life,” and Col. 1:13, “He rescued us from the domain of darkness, and transferred us to the kingdom of His beloved Son”).
The NT does not speak of people as in a progression becoming children (Roman Catholic theology is mistaken on this point, see the Catechism, par. 1989 and 1995), but declares that Christians are children of God. John 1:12-13 is clear: “to those who believe in His name, who were born…of God.” Similarly, James 1:18 uses the birth imagery of regeneration to speak about the beginning of salvation: “In the exercise of His will He brought us forth by the word of truth, so that we would be a kind of first fruits among His creatures.” Scripture tells of Christians’ birth as a completed reality with implications for relationship and obligation in an ongoing way now. Since Christians are children, then they must respond to God as their father and respond to fellow believers as brothers and sisters, as in 1 Peter 1:22-23, “fervently love one another from the heart, for you have been born again.”
Regeneration is the new re-orientation to all reality because of an instantaneous renewal of personal identity (albeit nascent in function). Regeneration is the new reality that expresses in a particular way told as life in the Spirit by contrast to life according to the flesh (= the old self and deathly existence of independence from God).
My claim here is that regeneration is a gift provided in the NC. Jesus rebukes Nicodemus for not having understood regeneration (John 3:10) as a reality the man should have known about. How would he have known? The promises of a NC tell the substance of regeneration that Jesus clarifies by the birth metaphor. I think the particular reality of regeneration is the new heart, but this is necessarily joined with the other three features of the NC listed above. In a theo-logic order (which is a different order than they appear in the biblical text), the aspects of NC regeneration are as follows.
First, regeneration occurs as the result of the indwelling presence and action of the Spirit, once the Spirit of God has dislocated from the Jerusalem temple to inhabit and animate the body of Christ.
Second, the Spirit purifies the sinner to be a temple for God by applying the justification achieved through incarnation (= the gift of Jesus’ humanly achieved righteousness) and the cross (= expiation and propitiation of guilt for sin through penal substitution, fulfilling both goats in the Day of Atonement, Lev. 16). Accordingly, Christians are addressed uniformly in the NT as saints, “holy ones,” not as sinners (James 4:8 being the exception). I see this purification as a necessary condition for regeneration, since a polluted and guilty person could not be vitally united with God in a direct way (because God’s holiness would destroy that sinner). We also see purification in the OT in the language of forgiveness, reconciliation, consecration, and justification of individuals who walked with God and are termed saints, but this does not mean such people experienced regeneration. In other words, the continuity of some experiences across pre-OC (= Noah, Job, Abraham), OC, and NC eras does not entail continuity of all experiences. The newness of the NC that is contingent on the incarnation and cross must include unprecedented realities (cf. John 7:39).
Third, the Spirit of God creates a new core in the member of Jesus to make such a one a child of God, sourced in God, and born of God (“born from above”). The reality of a new heart, new self, new creation, and new spirit is the renewal of the person at the core of mind, emotion, and will (the biblical meaning of the “heart” metaphor, which may correspond partly to the brain). Partial experience of the New Covenant in a personal and individual participation in inaugurated eschatology is at work here. The Christian is re-made to belong to the new creation that will come in fullness later with bodily resurrection to fit the new creation of all things, heaven and earth.
Fourth, the new heart depends upon the indwelling presence and action of the Holy Spirit for proper functioning. If left to ourselves, then we would all, even with purification or innocence (as with Adam and Eve before sin) turn to evil. The new capacities are nascent and inchoate, requiring maturity through voluntary daily embrace of the Spirit’s filling-up of all personal experience and responsiveness. Actions are transformed from the inside out, and the inside reality of the new heart is co-authored by the indwelling Spirit. The Christian is a mixed existence of a core renewal in the midst of many deep attachments to the old self that the Spirit must progressively detach (= “the flesh”).
For these reasons, 1 John gives a stark contrast between those who are the children of God, and their counterparts who are the children of the devil. Belonging to God is based on being born of God. This is not merely a way of life, but a kind of existence made possible only because of regeneration. The difference is as between a dead horse and a live one. We might imagine the capacities of the dead one, but to do so is just as much an illusion as to think the child of wrath can reconcile herself to God, and that we somehow contribute to our own birth from God by any dead efforts we might muster.