Chapter three of John's Gospel is all about being Born Again.   What does this mean?  Jesus told Nicodemus that unless he was "Born Again", he would not see the kingdom of God (v3).   He was totally confused and yet as a teacher of Israel Nicodemus should have understood what this meant.  And as a member of the supreme Jewish council, he should have grasped the meaning of Old Testament prophecies about the new birth (v10).  For instance Ezekiel 36:26-27 where God said:

"I will give you a new heart and put a new spirit in you.
I will remove from you your heart of stone and give you a heart of flesh.
And I will put My Spirit in you and move you
to follow My decrees and be careful to keep My laws".

This is what it means to be "Born Again".  It means to experience a spiritual rebirth and to know an inner transformation of the sin-hardened heart.  This brings a change of direction of a person's life toward God.  Only the supernatural work by the Holy Spirit within us can accomplish such a dramatic a change.

John 3:15-18 reassures us that whoever believes in Jesus and His sacrifice for our sins on Calvary Him is not condemned by God.   The Apostle John goes on to say in verse 16:

"God so loved the world that He gave His one and only Son,
that whoever believes in Him shall not perish but have eternal life."

This links what God has done for us and what we must do.  God has provided eternal life in Jesus, while our part is to believe.   John 1:12 says:

"But as many as received Him, to them gave He power to become the sons of God,
even to them that believe on His Name."

Here, the apostle defined "believe" in terms of "receive" and in John 3:15, "believe" is defined in terms of "repent".  Repenting means to turn away from our old sinful life to God's way, and acknowledging that we are sinners who deserve eternal death and separation from God.  We ask God's forgiveness and receive Jesus into our hearts as our Lord and Saviour.  Receiving is putting our true belief in God and trusting God enough to open our hearts to His gift of Salvation that He wants to give us.

And so when Jesus says, "You must be born again", He simply means that to enter His kingdom, you must let God come into your life, and to let Him work there as He pleases.  If you have turned to God and you trust His promise to give you new life in Jesus, you have Eternal Life now!  And through the miracle of the new birth, your life on earth will become fresh and new.

God Bless!