The kingdom of God was manifested perfectly in the person and work of the man Jesus Christ. “For in him, all the fullness of God was pleased to dwell,” Paul wrote in Colossians 1:19. As Jesus lived on earth, every thought, action, and word was a kingdom thought, a kingdom action, and a kingdom word. The way in which he interacted with people—and the way in which he called people to account for the gift of life that the Father had given them—showed the world that there was a better way to live. It was possible, through imitation of the life and work of Christ, to be formed into the image of God. It still is. Yet that way of life was (and is) fraught with difficulty and peril, precisely because this way of living—kingdom living—stands opposed to all of the kingdoms that humankind has created throughout history. But it is this kingdom, the kingdom of God, which is eternal. It is “not of this world” (John 18:36), but rather it is heavenly and everlasting. The “kingdoms” of the world will continue to fight against the kingdom of God, but the kingdom of God has already prevailed in the finished work of Jesus Christ. Earthly kingdoms are as nothing to God. “All the nations are as nothing before him, they are accounted by him as less than nothing and emptiness . . . It is he who sits above the circle of the earth, and its inhabitants are like grasshoppers; who stretches out the heavens like a curtain, and spreads them like a tent to dwell in; who brings princes to nothing, and makes the rulers of the earth as emptiness” (Isaiah 40:17, 22-23).
The Gospel of Mark makes clear that “kingdom of God” is the very gospel that Jesus preached (Mark 1:15). And the Sermon on the Mount
(Matthew 5-7) shows us plainly how to live as children of the kingdom. It is essential to note that living in this way is not something that any of us can do on our own. We must be in Christ in order to be equipped to live as Christ lived. By placing our faith in God, and devoting ourselves to God’s way of life, the Father—through the Son, and by the power of his Holy Spirit—initiates in us a process of transformation that is intended to form us into his likeness. This is not earned or merited in any way. Rather, we are simply recipients of the righteousness of God. That righteousness is a gift from God, not a human achievement. It is only through our faith in the risen Lord Jesus Christ that we receive this gift. And it is only through receiving this gift that we are made able to live in imitation of Jesus. It is Jesus Christ himself who is our righteousness.
For consider your calling, brothers: not many of you were wise according to worldly standards, not many were powerful, not many were of noble birth. But God chose what is foolish in the world to shame the wise; God chose what is weak in the world to shame the strong; God chose what is low and despised in the world, even things that are not, to bring to nothing things that are, so that no human being might boast in the presence of God. And because of him you are in Christ Jesus, who became to us wisdom from God, righteousness and sanctification and redemption, so that, as it is written, “Let the one who boasts, boast in the Lord” (1 Corinthians 1:26-31).