The Kingdom of God is the central subject of Jesus' teaching and the unifying theme of the entire New Testament. John the Baptist announced it: "Repent, for the kingdom of heaven is at hand!" (Matthew 3:2). Jesus' first recorded sermon announced it: "Repent, and believe in the gospel" — and the gospel was "the time is fulfilled, and the kingdom of God is at hand" (Mark 1:15). He commanded us to seek it first (Matthew 6:33) and to pray for its coming ("Your kingdom come"). The Kingdom of God is not primarily a place; it is the reign of God — the sphere in which His will is done. It has three dimensions. First, there is an already dimension: the kingdom broke into history with Christ's first coming. "If I cast out demons by the Spirit of God, surely the kingdom of God has come upon you" (Matthew 12:28). The kingdom is present wherever Christ's lordship is confessed and His will obeyed. Second, there is a progressive dimension: the kingdom grows like a mustard seed from tiny beginnings to a great tree, like leaven that slowly works through dough (Matthew 13). Third, there is a not-yet dimension: the kingdom will be consummated at Christ's return, when every knee bows and every tongue confesses that Jesus Christ is Lord (Philippians 2:10-11). Holding all three together is essential. Those who deny the present kingdom (certain forms of dispensationalism) miss that Christ reigns now. Those who deny the future kingdom (full preterism, some social gospel traditions) miss that the full manifestation is yet to come. The kingdom is present wherever Christ is King, and it will one day fill the whole earth as the waters cover the sea.