Already, but not yet.
This brief and enigmatic statement reflects the thinking of historic Christians when it comes to eschatology (the study or doctrine of “last things”). It means that Christ’s kingdom has already been inaugurated (accomplished at his first coming), but not yet consummated (which will only take place at his glorious second coming).
Christ the King came into the world at his incarnation and, through that event, inaugurated his divine kingdom on earth. Thus, the kingdom of God through the Messiah has already begun. Jesus initiated his reign upon the earth via his tripartite offices as prophet, priest, and king.
In his prophetic role as teacher and preacher, Christ enunciated the truths about the eternal Kingdom of God. A major part of Jesus’ public ministry involved teaching (often through parables) about God’s kingdom (see especially Matthew and Luke). Christ’s dominion stands in stark contrast to the various kingdoms of humankind (such as ancient Rome) in terms of origin, values, and destiny.
As a priest Jesus Christ came in the form of the “suffering servant” (Isaiah 53), whereupon he died on a Roman cross to appease God’s just wrath against human sin. Through this role Christ provided a way for sinners to be forgiven and thus reconciled to a holy God (Romans 5:10). He is designated as the great High Priest (Hebrews 4:14) who makes it possible for sinners to enter into the eternal kingdom of God.
The glorious and kingly Son of God also conquered death by his bodily resurrection from the dead (1 Corinthians 15:17, 20). As risen Lord and King, Jesus holds dominion over sin, death, and hell. From the time of his ascension to his second coming his kingdom is a spiritual reign of truth, holiness, faith, hope, and love. He rules over his church through the Holy Spirit according to the Word of God. The gospel message calls believers to share the good news of Christ’s victory over sin, death, and evil with the entire world.
But Not Yet
The full consummation of Jesus Christ’s kingdom awaits his promised second coming. At the parousia (second advent, 1 Thessalonians 4:15–17), the Lord will appear as conquering Lord and Judge. He will perform his divine works by raising humanity’s dead, judging the nations, and banishing evil fully and forever (Revelation 20). He will then end this present cosmos and bring forth the new creation where his people will live and reign with their Lord forever.
It is important to note, however, that the different approaches to eschatology have different understandings as to how Christ’s kingdom relates to the period known as the millennium. For more on the different views of the millennium, see part 5 of this series.
Christians relate to Jesus’ kingdom in a state of “already, but not yet.” The Lord’s kingdom has come in Jesus Christ’s life, death, and resurrection, but we now await in expectation its final consummation in glory.
For an introduction to the topic of general eschatology, see Donald G. Bloesch, The Last Things. For a brief but helpful article on Christ’s roles, see “Offices of Christ” in the New Dictionary of Theology edited by Sinclair Ferguson, David Wright, and J. I. Packer.