As long as there are people, Christ will walk the earth as your neighbor, as the one through whom God calls you, speaks to you, makes demands on you. That is the great seriousness and great blessedness of the Advent message. Christ is standing at the door; he lives in the form of a human being among us. Do you want to close the door or open it?
It may strike us as strange to see Christ in such a near face, but he said it, and those who withdraw from the serious reality of the Advent message cannot talk of the coming of Christ in their heart, either.
…Christ is knocking. It’s still not Christmas, but it’s also still not the great last Advent, the last coming of Christ. Through all the Advents of our life that we celebrate runs the longing for the last Advent, when the word will be: “See, I am making all things new” (Rev. 21:5).
The Advent season is a season of waiting, but our whole life is an Advent season, that is, a season of waiting for the last Advent, for the time when there will be heaven and a new earth.
In a letter from Dietrich Bonhoeffer to his parents, November 29, 1943, written from the Tegel prison camp. (From page 2 of God is in the Manger: Reflections on Advent and Christmas from the writings of Bonhoeffer, translated by O.C. Dean Jr. and edited by Jana Riess.)