He needed to be born again.
The first question, then, is why the new birth is necessary. But once we understand that Jesus was speaking about receiving life from God, another question naturally follows:
What actually happens when a person is born again?
The expression has become so familiar that it is easy to use it without considering what it describes. People speak about being born again, giving their lives to Christ, becoming Christians, or having an encounter with God. But the language of birth tells us that something has happened to the person himself.
The new birth is not simply a decision to live differently. It is not merely the adoption of Christian beliefs or the beginning of religious activity. It is the beginning of a new life from God.
So what changes when that life is received?
God Gives What We Could Not Produce
The first thing we must understand is that the new birth begins with God.
Jesus told Nicodemus, “That which is born of the flesh is flesh, and that which is born of the Spirit is spirit” (John 3:6). There is something natural life cannot produce. Human ability can develop the natural person, but it cannot generate spiritual life.
A person can change his habits. He can become more disciplined, more knowledgeable, more moral, or more religious. He can decide to attend church regularly, read the Bible, pray, and avoid certain behaviours. All of these things can have value, but none of them can create the life Jesus was describing to Nicodemus.
Life has to come from God.
This is why the Christian life cannot be understood simply as an improved version of the natural life. Christianity begins with something God does that human effort cannot accomplish.
The person who is born again has received something he could not produce for himself.
That is the starting point for everything else.
A Person Is Brought Into a New Relationship With God
The new birth changes more than the person's religious identity. It changes his relationship with God.
Sin had separated humanity from God, but the Gospel announces reconciliation through Christ. Paul writes that “God was in Christ reconciling the world to Himself” (2 Corinthians 5:19).
This is important because salvation is sometimes presented mainly as a way of escaping punishment. Scripture presents something much greater. God is bringing people back to Himself.
The person who is born again is no longer relating to God merely as the Creator who made him or as the Judge before whom he will one day stand. Through Christ, he is brought into a relationship with God.
The New Testament therefore speaks about believers as God's children.
Paul writes:
“For as many as are led by the Spirit of God, these are sons of God. For you did not receive the spirit of bondage again to fear, but you received the Spirit of adoption by whom we cry out, ‘Abba, Father.’”
— Romans 8:14–15
This is not simply a change in vocabulary.
The person who has been brought to God through Christ now belongs to Him in a new way. The Christian life begins to make sense when it is understood from this relationship. We are not trying to become God's children by our religious performance. We are learning to live as those whom He has brought into His family.
The new birth therefore begins with belonging.
God Begins His Work Within the Person
The new relationship with God is accompanied by an inward work.
Long before Christ came, the prophets spoke about what God would do in the hearts of His people. Through Ezekiel, God promised:
“I will give you a new heart and put a new spirit within you.”
— Ezekiel 36:26
God did not promise merely to give His people better instructions. He promised to do something within them.
This is important because humanity's problem is deeper than a lack of information. A person may know what is right and still be unable to live consistently from that knowledge. The problem reaches into the heart.
The New Covenant therefore involves God working within the person.
This does not mean that every old pattern disappears immediately. It does not mean that a Christian becomes mature in one moment. It means that God has begun something inside the person that was not there before.
The new birth is therefore not simply a change of direction that a person produces by determination. It is the beginning of an inward work of God.
And this is where the Holy Spirit becomes central.
The Holy Spirit Becomes the Source of the New Life
Jesus told Nicodemus that a person must be born of the Spirit (John 3:5–6).
The Spirit is not simply an influence that helps a Christian behave better. He is the One through whom God gives spiritual life.
Jesus later told His disciples that the Spirit would be with them and would be in them (John 14:16–17). Paul told believers that their bodies are temples of the Holy Spirit (1 Corinthians 6:19).
This gives us a different picture of the Christian life.
God does not give a person new life and then leave him to maintain that life through human strength. The Spirit of God is involved in the life of the believer.
The Christian therefore has a new source from which to live.
This does not remove the need for obedience. It changes the foundation from which obedience takes place.
The believer is not trying to manufacture the life of God by his own strength. He is learning to respond to the Spirit who has been given to him.
This is one of the great realities of the New Covenant: God does not merely tell His people how He wants them to live. He gives His Spirit to dwell among them and within them.
The difference is important.
The Person Is Now Described as a New Creation
Paul uses another expression to describe what has happened:
“Therefore, if anyone is in Christ, he is a new creation; old things have passed away; behold, all things have become new.”
— 2 Corinthians 5:17
These words are easy to read without stopping to consider their weight.
Paul does not say that the person has simply turned over a new leaf. He describes what has happened to someone who is in Christ in terms of new creation.
This does not mean that his memories are erased or that his personality disappears. It does not mean that every consequence of his former life immediately disappears. It does not mean that he becomes fully mature in a moment.
It means that his life has entered a new reality in Christ.
The person who once lived without God as the source and centre of his life has been brought into Christ. The person who was separated from God has been reconciled to Him. The person who lived according to the limitations of natural life has received life from God.
Something genuinely new has begun.
This is why the Christian life cannot be reduced to adding Christian beliefs to an unchanged natural existence.
There is a new beginning.
New Life Creates a New Capacity for Living
If God has given a person new life, that life will begin to affect the way the person lives.
This is where we must understand the difference between receiving life and learning to live from that life.
The new birth gives the person spiritual life, but he still has to learn how to walk with God. His mind has been shaped by years of experiences. His habits have been formed over time. His desires have been trained by what he has seen, loved, feared, and pursued.
The fact that these things do not disappear instantly does not make the new birth unreal.
Rather, it shows why growth is necessary.
The Spirit begins producing something in the believer's life. Paul calls it “the fruit of the Spirit” and describes it as “love, joy, peace, longsuffering, kindness, goodness, faithfulness, gentleness, self-control” (Galatians 5:22–23).
These qualities are not simply a list of behaviours that a Christian must force himself to perform. They describe the kind of fruit the Spirit produces.
The new life therefore begins to affect what a person loves, what he values, what he is willing to surrender, how he responds to others, and what kind of person he desires to become.
The change may not appear all at once.
But the source has changed.
The New Birth Gives Life, but Growth Takes Time
This distinction is essential.
A newborn child is completely alive, but he is not completely developed.
He has life, but he still has to grow.
The same is true spiritually.
A person can genuinely be born again and still need to grow in understanding, character, wisdom, obedience, discernment, faith, and the practical knowledge of walking with God.
Peter therefore tells believers:
“But grow in the grace and knowledge of our Lord and Savior Jesus Christ.”
— 2 Peter 3:18
Notice the command: grow.
Growth would make no sense if there were no life to grow from.
The new birth does not mean that everything God intends to accomplish in a person has already been completed. It means that God has begun something that must now develop.
This helps us avoid two opposite mistakes.
The first is thinking that human effort can produce spiritual life. It cannot.
The second is thinking that receiving spiritual life means there is nothing more to learn. That is also wrong.
God gives life, and then He teaches us how to walk in that life.
The new birth is therefore the beginning of the Christian journey, not its destination.
The New Life Must Become the Life We Live
Paul says that believers are to “walk in newness of life” (Romans 6:4).
That word walk is important.
God's purpose is not merely that we should know that something happened to us when we believed. The life we have received is meant to become the life we learn to live.
This reaches into ordinary parts of our lives.
It affects what we do when we are offended. It affects how we respond to temptation. It affects what we do with our time, what we pursue, what we fear, what we trust, how we treat people, and how we respond when nobody is watching.
The Christian life is therefore not sustained by constantly trying to become spiritually alive again.
A believer who fails does not need to be born again every morning.
He needs to learn how to walk in the life he has already received.
This is why Scripture, prayer, obedience, fellowship with God, and the work of the Holy Spirit matter. They are not ways of manufacturing spiritual life. They are part of learning to live from God.
The difference is important.
We do not obey in order to create the life of God within us. We learn to obey because God has given us life and has called us to live from Him.
What Has Actually Happened?
So, what has happened when a person is born again?
God has done something that the person could never accomplish by himself.
He has given life from the Spirit. He has brought the person into reconciliation with Himself through Christ. He has brought him into a new relationship with God. He has given His Spirit. He has begun an inward work. The person is described as being in Christ and as a new creation.
And yet the story does not end there.
The person who has received life must learn to live from that life.
He must grow.
He must learn.
He must allow the truth of God to reshape his thinking. He must learn obedience. He must learn dependence upon the Spirit. He must grow in his knowledge of Christ.
The presence of these processes does not mean the new birth has failed. They are part of what follows the new birth.
Jesus did not tell Nicodemus merely to improve the life he already possessed.
He told him that he needed a life that could only come from above.
And when that life is given, God begins something new in the person.
That new life changes his relationship with God. It changes his standing before God. It gives him the Spirit. It gives him a new beginning in Christ. It gives him a new source from which to live.
But then another question arises.
If this is true, why can people who have genuinely received new life still struggle with old desires, old patterns, temptation, weakness, and sin?
If the life is new, why does the struggle remain?
That question matters because many believers become confused at this point. They begin to wonder whether their struggles prove that they were never truly born again.
But perhaps we are asking the wrong question.
Perhaps the presence of struggle does not mean that no new life was received. Perhaps we need to understand what happens after new life has begun.
That is where the next part of the journey begins.