To be born of the Spirit means that something within the very depths of our being has changed. Our spirits have been reborn after we had been dead in sin. In this rebirth, the Holy Spirit has brought us back to life, affecting a spiritual resurrection. The human spirit was formerly dormant while dominated by our intellect, will, and emotions. Our own self-will kept us from submitting to God.
We were dead in our sins, but now we have been made alive with Christ (Ephesians 2:1, 5). Now, with the Spirit of Christ indwelling, our bodies are dead because of sin, but our spirits have been made alive because of righteousness (Rom. 8:10). So we are now dead to the old way of self-indulgence and enlivened by the Spirit to do what is right. The Spirit now bears witness with our spirits that we are children of God (Rom. 8:16).
While our spirits may formerly have been willing to do good, our flesh was weak (Matt. 26:41). But having been born of the Holy Spirit, the human spirit is resurrected and empowered to overcome the flesh. That which is born of flesh is flesh; and that which is born of Spirit is spirit (John 3:6). Just as physical birth brings about new life, so does spiritual birth. So having been born of the Holy Spirit, our human spirits have been regenerated. Each one born of the Spirit has become a new creation (2 Cor. 5:17).
So being born from above, or born again, is our spiritual rebirth. But where I think a lot of Christians go wrong is to view the new birth as a mere legal transaction in which our sin is exchanged for Christ's righteousness. In this view, we simply uphold our end of the agreement by submitting to the "plan of salvation." In so doing we trigger the mechanism that releases God's forgiveness. We're declared righteous and so our ticket is punched. So righteousness is a kind of "legal fiction" in which God pretends that we are righteous whether we live that way or not.
Evangelicals are especially fond of speaking of "imputed righteousness" in which the righteousness of Christ is transferred to the believer. I have no trouble with imputed righteousness, but there is more to spiritual birth than just a status change. We have done more than cross over from a lost state to a saved state. We don't just get a new name on the birth certificate, but it's the beginning of a whole new life.
The result of new birth is not just "imputed righteousness," but also "empowered righteousness." Through the Holy Spirit's indwelling we are now empowered to live righteously. We aren't just freed from the penalty of sin, but also from its power over us.
While God's Law had defined sin, it could not empower folks to overcome it. That is because the Law was weak through the flesh (Rom. 8:3). The fault was not with God's law, but with humans who disobeyed it. Since everyone has disobeyed, no one was ever counted worthy of God. No one could earn a place in his Presence.
But what the Law could not achieve, God did by sending his Son to take the condemnation for our sins. Jesus bore the penalty so we could be acquitted of our wrongs. With our debt being paid, the obstacle of sin that blocked us from God's Presence has been removed. So now God's Presence has come to abide within us.
God's Holy Spirit within empowers us for holy living so "that the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit" (Rom. 8:4). For righteousness to be fulfilled in us does not simply mean that Christ's righteousness has been transferred to us (although I believe this has happened). But the Spirit actually enables us to live righteously.
We could speculate all day about how the Spirit does this. Some deny that he does anything since his work cannot be explained. But such is the elusive nature of the Spirit who, like the wind, "blows wherever it pleases. You hear its sound, but you cannot tell where it comes from or where it is going. So it is with everyone born of the Spirit" (John 3:8). We cannot totally comprehend or explain the work of the Spirit in our lives. Like the wind, we cannot control him. We cannot analyze him in a beaker or on a Petri dish. The Spirit is beyond our fathoming.
So what is the importance of our affirming the Spirit's indwelling? I think the bottom line for us is this: Knowing that the Spirit is there leaves us without excuse for living ungodly lives. We cannot excuse an unrepentant life by claiming, "I was born that way"; or "I cannot change. It's just the way I am"; or "It's just how my parents raised me." If God has given all we need pertaining to life and godliness, including the indwelling of his Spirit, then we cannot claim powerlessness. We don't have to be enslaved to sin. Temptation and addiction can be overcome, but not by ourselves. We must yield to a power from on high.
Just as we are not justified by our own works, nor are we sanctified by our efforts alone. As the flesh could not save us, nor are we capable of holy living by our own willpower. There is someone there assisting and empowering us.
We now have an advantage that we lacked prior to new birth. While controlled by the flesh, we could not please God because "the mind governed by the flesh is hostile to God. It does not submit to God's law, nor can it do so" (Rom. 8:7-8). But we have now been equipped and empowered to obey God through the Spirit's guidance and influence.
To be born again is to step out of the realm of the flesh and into the realm of the Spirit. In this new realm we can now live for God. I'm not talking about sinless perfection. Nor am I saying that those outside of Christ are totally depraved and incapable of doing any good at all. What I'm talking about is release from the ensalvement to sin and bondage to addiction.
The Scripture is clear that a great change occurs when we step out of the old realm and into the new. The question is whether we're trusting in the Spirit to change us or if we're still making excuses.