This is an excerpt from a great post on regeneration that was published today on the Ligonier Ministries Blog. If you have time, I would encourage you to visit their site and read the entire article.
It is for this reason that Jesus told Nicodemus, "You must be born again" (John 3:7). The spiritually dead cannot enter God's holy presence. "Unless one is born again he cannot see the kingdom of God" (John 3:3). In order to see God's kingdom, then, the spiritually stillborn must be brought to life. There must be spiritual resurrection.
There must be new life, eternal life. "You must be born again." Jesus' words befuddled Nicodemus. He said to Jesus, "How can a man be born when he is old? Can he enter a second time into his mother's womb and be born?" (John 3:4). Here Nicodemus gives us a textbook example of missing the point.
Nicodemus is not alone. There are a large number of professing Christians who miss the point. To hear some tell it, you would think Jesus merely said, "You must be well again." According to many, we are not spiritually dead but are simply sick. We are on our death beds, and Jesus offers us the cure. All we have to do is reach out and take it. Or we are drowning and Jesus offers us a life buoy, and all we have to do is grab it to save our lives. The picture painted by Jesus and the apostles, however, is much more bleak. In our natural Adamic state, we are not on our sick beds. We are in the grave. We are not flailing about on the surface of the sea. We are lifeless at the bottom of the ocean. We are dead.
This is the point that Nicodemus and we must understand. When Jesus tells Nicodemus he must be born again, He is indicating that this is not something Nicodemus can do himself. Just as we had no control over our physical birth, we do not control our spiritual birth. It is the sovereign work of the Holy Spirit. Those who say that we are only spiritually wounded will say that we can be regenerated, born again, by placing our faith in Christ. This, however, puts everything precisely backwards. We do not believe in order to be regenerated; we must be regenerated in order that we might believe. Regeneration precedes faith.
Our spiritual situation is similar in some ways to that of Lazarus in the grave (see John 11). Lazarus was dead. He could do nothing in and of himself to gain new life. Jesus commanded Lazarus to come forth from the grave, but Lazarus could not respond unless God first gave him life. In the same way, we are spiritually dead and can do nothing to gain spiritual life. Jesus commands us to believe in Him, but we cannot respond unless God first gives us spiritual life. Jesus gives us this new life because he has overcome death, once and for all. As Peter explains, "According to his great mercy, he has caused us to be born again to a living hope through the resurrection of Jesus Christ from the dead" (1 Peter 1:3).
If you are a Christian, consider what God has done for you. Consider the fact that you were born dead in sin. Jesus came to your grave. He commanded you to come forth and gave you spiritual life and faith. Now you have been born again and are an adopted child of God (John 1:12). You are a co-heir with Christ. And although your physical body will still die, you can rest secure in the hope of the resurrection. Those in Christ will be made alive (1 Corinthians 15:22). Our present body is perishable, but it will be raised imperishable, never to die again. When God raises us, death will finally be swallowed up in victory.
—Keith A. Mathison Tabletalk Magazine, June 2008
I love the way that Jesus explained this to the Jews when he was at the temple in Jerusalem:
The works that I do in my Father's name bear witness about me, but you do not believe because you are not part of my flock. My sheep hear my voice, and I know them, and they follow me. I give them eternal life, and they will never perish, and no one will snatch them out of my hand. My Father, who has given them to me, is greater than all, and no one is able to snatch them out of the Father's hand. I and the Father are one.
— John 10:25-30, ESV
Jesus makes it clear that belief (or faith) is the result of our rebirth and inclusion in the family of Christ, not the grounds for it. Regeneration precedes faith. Soli Deo Gloria!