Although the kingdom of God was among the people of Israel in the Old Testament, it was taken away from them in the New Testament and given to the New Testament believers (Matt. 21:43). Thus, it had a new beginning and became the church (Matt. 16:18-19).
John the Baptist came out to preach the baptism of repentance as the opening of God’s New Testament economy, asking people to have a turn for the kingdom of the heavens (Matt. 3:2). Then Jesus came and continued the preaching of His forerunner John the Baptist, telling people to repent for the kingdom of the heavens (Matt. 4:17). This indicates that God’s New Testament economy is focused on His kingdom. We need to repent—have a change in our mind, have a turn in our pursuit of life—and believe in the gospel that our sins may be forgiven and that we may be regenerated by God to have the divine life, which matches the divine nature of the kingdom of God. Thus we may enter into the kingdom of God (John 3:3, 5).
In John 3:3 the Lord said, “Truly, truly, I say to you, unless a man is born anew, he cannot see the kingdom of God,” and in verse 5 He said, “Truly, truly, I say to you, unless a man is born of water and the Spirit, he cannot enter into the kingdom of God.” The Lord’s words here reveal that regeneration is the unique entrance into the kingdom of God.
A kingdom is always related to life. The vegetable kingdom is related to the vegetable life, and the animal kingdom is related to the animal life. If you want to share in a certain kingdom, you first need the life of that kingdom. Therefore, in order to enter into the kingdom of God, man needs to be regenerated, that is, to receive God’s life in addition to man’s natural life.
The kingdom of God is not only the reign of God, but also the realm and sphere of the divine life. In order to participate in the reign of God and to be in the divine realm, we need the divine life. Only those who have the divine life can be in the divine realm and share the divine kingdom in which God reigns. Thus, we need to be regenerated that we may have the divine life which enables us to enter into the divine realm and participate in the divine kingdom. Even if we were not fallen or sinful, we would still need to be born again and receive the divine life, because regardless of how good, pure, and clean our human life might be, it cannot qualify us to enter into the divine kingdom. Only the divine life qualifies us to enter into the divine realm. Only the life of God meets the divine requirements of the kingdom of God. Regeneration is the unique entrance into the kingdom of God.
Romans 12 through 16 is concerned with the church life. Romans 14:17 says, “For the kingdom of God is not eating and drinking, but righteousness and peace and joy in the Holy Spirit.” This proves that God’s kingdom life is the church life. The kingdom of God is neither eating nor drinking. The kingdom of God is righteousness toward ourselves, peace toward others, and joy with God in our spirit. These items— righteousness, peace, and joy—are the expressions of Christ. They are the characteristics of the kingdom of God as well as the reality of the church life today. Hence, the kingdom in this age is the church. The book of Acts, which is mainly concerned with the producing, the establishing, and the spreading of the church, stresses both the kingdom of God (1:3; 8:12; 14:22; 19:8; 20:25; 28:23, 31) and the church (5:11; 8:1, 3; 9:31; 11:22, 26; 12:1, 5; 13:1; 14:23, 27; 15:3-4, 22, 41; 16:5; 18:22; 20:17, 28). This shows that the church today is the kingdom of God.