I believe it was the German Lutheran pastor and theologian Helmut Thielecke who observed that God has not entered the world in Christ only to shut the door of eternity behind him. To confess the gift of hope in Christ is to confess a hope that is not and cannot be grounded in ourselves. The very fact of the Incarnation of God in Jesus, the fact that eternity has entered history, is a sign of this. The fulfillment of the future is not simply the culmination of humanity’s projected dreams of peace and justice. The fulfillment of God’s kingdom will be just that, God’s bringing about something utterly new and not the coming together of strands by which humanity weaves the dreams of a utopia.
Although the fulfillment of the future is taken out of our hands, the promise of a new heaven and new earth sets up both goals and boundaries for our lives now.
Since we know the broad parameters of the kingdom are sketched in the terms of faith, hope and love, the temporal goal of the Christian and the Church as a whole must be to fight against the powers in this life that would turn hope into despair, turn faith or trust inward on the self or on history, and pervert love into an endless number of misplaced loyalties which in the end is idolatry.
The boundaries of the promised kingdom also keep us from wandering off into Marxian, utopian dreams which would leave all prior generations in death with no share in its’ blessings. Instead the Christian hope reflects our belief in the resurrection of the dead, the sign that all people will be in proximity to the fulfillment of God’s promises, according to His will.