Repent for the Kingdom of God is at hand
"Truly, truly, I say to you, unless one is born again, he cannot see the Kingdom of God." Nicodemus said to him, "How can a man be born when he is old? Can he enter a second time into his mother's womb and be born?" Jesus answered, "Truly, truly, I say to you, unless one is born of water and the Spirit, he cannot enter the Kingdom of God." (John 3:3-5).
Jesus taught Nicodemus that one cannot enter the Kingdom of God unless he was born again. To be born again, regenerated, is to enter the Kingdom of God. The people of the Old Testament could not possibly have been born again because that Kingdom would not be a reality until Jesus rose from the dead and was given all authority and power in heaven and on earth.
The Promised Kingdom
The prophet Daniel prophesied about this coming Kingdom. When the angel Gabriel encounters Mary, he tells Mary that God is going to give her son Jesus this Kingdom.
In the days of those kings the God of heaven will set up a Kingdom which will never be destroyed, and that Kingdom will not be left for another people. It will crush and put an end to all these kingdoms, but it will itself endure forever." (Daniel 2:44).
"I kept looking in the night visions, and behold, with the clouds of heaven One like a Son of Man was coming, And he came up to the Ancient of Days and was presented before Him. And to Him was given dominion, glory and a Kingdom, that all the peoples, nations and men of every language might serve him. His dominion is an everlasting dominion which will not pass away and his Kingdom is one which will not be destroyed." (Daniel 7:13-14).
He will be great, and will be called the Son of the Most High, and the Lord God will give to him the throne of his father David, and he will reign over the house of Jacob for ever, and of his Kingdom there will be no end." (Luke 1:32-33).
Daniel preaches the future Kingdom of God. When we turn to the pages of the New Testament we find that Kingdom being announced for the first time.
The Kingdom of God is at hand
John the Baptist came preaching the Kingdom of God was at hand (Mk 1:15). The Greek term "at hand" is the Greek word agizzo which means "near" in both a spatial and chronological sense, that you can reach out and touch it, and it was very near in time. Matthew refers to this Kingdom as the Kingdom of Heaven (Mt 3:2). Jesus also preached the same message (Mt 4:17,23; Luke 4:43) and taught his disciples to preach this message (Mt 10:7; Luke 9:2,11; 10:9). The Kingdom of God was a new reality for the people of Israel and this is why John was calling them to repentance, to prepare them for their coming King. Jesus also taught many parables to tell the disciples what the Kingdom of God would be like. He also taught the Pharisees that if he drove out demons by the Holy Spirit the Kingdom was upon them and they should not be looking here and there for it because it would be in their midst (Mt 12:28; Luke 17:21). The Kingdom was not a place, but Kingship reign of God on the earth and Jesus taught his disciples to pray to the Father, "your Kingdom come." He taught the people that the Kingdom had been forcing its way into the world since John the Baptist began preaching (Mt 11:12). When Jesus rose from the dead, he tells the disciples God have given him authority over all heaven and earth. And then we find the disciples went out preaching the good news of the Kingdom of God (Acts 8:12; 14:22; 19:8; 20:25; 28:23,31). The Kingdom of God was a brand new reality.
The Firstborn of the Dead
Born again believers are now the subjects of the Kingdom of God and citizens of that heavenly reality. For now, they are citizens of the Kingdom of Heaven sojourning and living in a foreign land and long for their heavenly home. They are heirs of that Kingdom and await their glorious inheritance. They long to enter into the full reality of that Kingdom in their resurrections when Jesus comes in glory. Because they are in the Spirit they now experience the realities of the Kingdom and have access to the heavenly throne of God. When Jesus comes again his Kingdom reign will be complete and total when he puts all his enemies under his feet. For now, his Kingdom includes only those individuals who have subjected themselves to him and serve him as their Lord - born again Christians. These are those who are born out of the dead through Jesus, the firstborn of the dead.
Jesus was the firstborn of the dead (Rom 8:29; Col 1:18; Rev 1:5; cf. Ac 13:33; Heb 1:5). Paul teaches us that when we are baptized into Christ we die with him and are raised with him (Rom 6:3-6; Col 2:11-12). In this way, we share in his death and resurrection, that is, we die to our old humanity and are born anew into the new risen and glorified humanity of Jesus, new creations. Jesus was the first man to be born into the Kingdom of God so that he would be pre-eminent in every respect. (1 Cor 15:42-50; Col 1:15-18). Until Jesus rose from the dead no one could share in his death and resurrection and be born again because it is through the risen man of heaven that one is born again. His divine humanity made it possible for the first time and this is what Peter was preaching on the day of Pentecost. Jesus was the firstborn among many brothers.
The Least is Greater than John
John the Baptist was a prophet of God and the last of the Old Testament prophets. John came to announce a radical change, the coming Kingdom of God and called all Judea to repent to prepare themelves for their coming King. Like all prophets the Spirit of God was upon him. Yet like all prophets, the Spirit of God did not come down and remain as a deposit of eternal inheritance. Jesus would be the first man upon whom the Spirit would come down and remain. Jesus teaches that John the Baptist was the greatest of all men, those "born of a woman." Yet, the very least in the Kingdom of God is greater than John. You see, John the Baptist died before Jesus died and was not born again into the Kingdom of God and the least of those who are born again are greater than John. Jesus taught, "that which is born of flesh is flesh and that which is born of Spirit is spirit. You must be born again." To be "born of a woman" is to be born of the flesh, a normal human birth. In this respect there was none greater than John. But in the respect of the new birth into the Kingdom of God, everyone is greater than John. John the Baptist was not born again because such a thing would not be possible until Jesus rose from the dead.
The Keys of the Kingdom
At Caesarea Philippi, Jesus asks his disciples a very important question and Peter confesses that Jesus is the Christ. Here Jesus tells Peter he will build his church (future tense) and he will give Peter the keys to the Kingdom (future tense). We see Jesus alluding to a similar idea at Luke 22:29. In the upper room the risen Jesus gives them authority when he breathes upon them and said, "As the Father sent me, now I send you. Receive the Holy Spirit." And at Matthew 28:18-19, the risen Jesus tells them he has been given all authority on heaven and earth and commissions his disciples to baptize all nations in his name, that is, they are to gather people into the Kingdom of God.
You must be born again
The Kingdom of God was a new reality to the people of Israel and John the Baptist announced this new Kingdom to them, calling them to repentence to prepare the way of the Lord. This was the Kingdom that Daniel had prophesied and Gabriel had announced to Mary, the mother of the one who would be given that Kingdom. Jesus taught his disciples that some would not see death until they saw him coming in his Kingdom. Judas was not one of them. Upon his resurrection, Jesus was given that authority (Mt 28:18; Acts 2:36) when God raised him up to sit at his right hand and entry into that Kingdom became a possibility.
In order to enter the Kingdom of Heaven, one must be born again. But this was not possible until Jesus was born again, the firstborn of the dead. Jesus was born of the flesh in Bethlehem and died in Jerusalem on the cross. But he was born again of the Spirit from the dead on the third day. He was dead and needed to be born again to live again. He is the firstborn out of the dead so that he might be the firstborn among many brothers who share his death and resurrection and so that he might be pre-eminent in that Kingdom in every respect. Jesus rose from the dead and was given all authority by God to rule and began setting up his Kingdom and his church. His first officers of his Kingdom were his apostles who were to gather subjects into his Kingdom from all nations through the new birth into his resurrection life. His Kingdom was a new reality and new birth into this reality was most definitely not an Old Testament possibility.