Kingdom of the heavens is a term used exclusively by Matthew, indicating that the kingdom of the heavens differs from the kingdom of God (see chart on pp. 30-31), the latter being mentioned in the other three Gospels. The kingdom of God is God's general reign from eternity past to eternity future. It comprises eternity without beginning before the foundation of the world, the chosen patriarchs (including the paradise of Adam), the nation of Israel in the Old Testament, the church in the New Testament, the coming millennial kingdom (including its heavenly part, the manifestation of the kingdom of the heavens, and its earthly part, the Messianic kingdom), and the new heaven and new earth with the New Jerusalem in eternity without end. The kingdom of the heavens is a specific section within the kingdom of God, a section composed only of the church today and the heavenly part of the coming millennial kingdom. Hence, in the New Testament, especially in the other three Gospels, the kingdom of the heavens, a section of the kingdom of God, is also called "the kingdom of God." In the Old Testament the kingdom of God, generally, already existed with the nation of Israel (Matt. 21:43); the kingdom of the heavens, specifically, had still not come, and it only drew near when John the Baptist came (Matt. 3:1-2; 11:11-12).
According to Matthew there are three aspects concerning the kingdom of the heavens: the reality, the appearance, and the manifestation. The reality of the kingdom of the heavens is the inward content of the kingdom of the heavens in its heavenly and spiritual nature, as revealed by the new King on the mountain in chs. 5—7. The appearance of the kingdom of the heavens is the outward state of the kingdom of the heavens in name, as revealed by the King on the seashore in ch. 13. The manifestation of the kingdom of the heavens is the practical coming of the kingdom of the heavens in power, as unveiled by the King on the Mount of Olives in chs. 24—25. Both the reality and the appearance of the kingdom of the heavens are with the church today. The reality of the kingdom of the heavens is the proper church life (Rom. 14:17), which exists in the appearance of the kingdom of the heavens, known as Christendom. The manifestation of the kingdom of the heavens is the heavenly part of the coming millennial kingdom, which is referred to as the kingdom of the Father in 13:43; the earthly part of the millennial kingdom is the Messianic kingdom, which is referred to as the kingdom of the Son of Man in Matt. 13:41, and which is the restored tabernacle of David, the kingdom of David (Acts 15:16). In the heavenly part of the millennial kingdom, which is the kingdom of the heavens manifested in power, the overcoming believers will reign with Christ for a thousand years (Rev. 20:4, 6); in the earthly part of the millennial kingdom, which is the Messianic kingdom on earth, the saved remnant of Israel will be the priests and will teach the nations to worship God (Zech. 8:20-23).
If we are poor in spirit, the kingdom of the heavens is ours: we are in its reality now in the church age, and we will share in its manifestation in the kingdom age.