"...Unless one is born again, he cannot see the kingdom of God ... unless one is born of water and the Spirit, he cannot enter the kingdom of God." John 3:3,5; Read John 3:1-8
When Nicodemus, a Pharisee and ruler of the Jews, came to Jesus by night, Jesus told him that, unless a man is born again, he cannot see the kingdom of God (John 3:3). And so also today, unless one is born again, he isn't able to see or understand what the kingdom of God really is.
When Nicodemus questioned Jesus about how a grown man could be born again, Jesus told him, "Most assuredly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God. That which is born of the flesh is flesh, and that which is born of the Spirit is spirit" (John 3:5,6).
It wasn't enough to be a descendant of Abraham or to be a part of a strict religious sect of the Jews; a spiritual rebirth was needed. Nor is it enough today to be born into a religious family or to be a member of a church denomination or organization; one must be born of God!
In John 1:10-13, we read of Jesus, the eternal Word made flesh: "He was in the world, and the world was made through Him, and the world did not know Him. He came to His own, and His own did not receive Him. But as many as received Him, to them He gave the right to become children of God, to those who believe in His name: who were born, not of blood, nor of the will of the flesh, nor of the will of man, but of God."
As the Greek text of John 3:5 makes clear, this rebirth of which Jesus speaks is "of water and the Spirit" (EX UDATOS KAI PNEUMATOS); it is "the washing of regeneration and renewing of the Holy Spirit" (Tit. 3:5) and "the washing of water by the word" (Eph. 5:26). It is the gracious working of God's Spirit through God's Word and the waters of baptism to offer and guarantee to the penitent sinner who looks in faith to Christ Jesus and His cross the forgiveness of sins and eternal salvation which Jesus purchased with His blood, shed upon the cross (cf. Acts 2:37-39; 22:16).
The Pharisees had rejected the counsel of God and did not repent and receive the baptism of John the Baptist for the remission of their sins (cf. Mark 1:4; Luke 7:30). Nicodemus, a Pharisee, needed to acknowledge his own utter sinfulness before God and be baptized into the name of Christ Jesus for the forgiveness of his sins, and God's Spirit would work in him a new spiritual life and make him a part of God's eternal kingdom through faith in Christ.
And, of course, nothing has changed today. Jesus' Word is still true. Unless you acknowledge your utter sinfulness before God and turn to Him and receive the forgiveness of sins that Christ won for you on the cross and which God offers and gives through the word of the Gospel and Christian Baptism, you, too, cannot enter into God's eternal kingdom.
It is as Peter testified on the day of Pentecost (Acts 2:38-39): "Repent, and let every one of you be baptized in the name of Jesus Christ for the remission of sins; and you shall receive the gift of the Holy Spirit. For the promise is to you and to your children, and to all who are afar off, as many as the Lord our God will call." It is as the Apostle Paul was told by Ananias (Acts 22:16): "And now why are you waiting? Arise and be baptized, and wash away your sins, calling on the name of the Lord."
Only through faith in Jesus can one receive the forgiveness of sins and life everlasting! Repent and be baptized in His name!
Dearest Lord Jesus, I know that I am a sinner and have not lived according to your holy and perfect will for me. I have broken your commandments and deserve everlasting punishment in hell for my sins. Graciously forgive me and wash away my sins for the sake of your holy and precious blood, shed on the cross for me. Amen.