There’s a somewhat famous quote from Bonhoeffer’s Letters and Papers from Prison (November 21, 1943, pp. 188-89) on the nature of Advent: “By the way, a prison cell like this is a good analogy for Advent; one waits, hopes, does this or that — ultimately negligible things — the door is locked and can only be opened from the outside.”
Interestingly in the same letter Bonhoeffer mentions how much he misses table fellowship and how he’s begun praying Luther’s morning and evening blessing every day. He then says: “Don’t be alarmed! I will definitely not come out here as a ‘homo religiosus’! Quite the opposite: my suspicion and fear of ‘religiosity’ has become greater here than ever.” So then, perhaps we must say that Advent, according to Bonhoeffer’s prior analogy, as a prison cell that can only be opened from outside, should be seen as the end of religion. All religion must have a door that can, at least partially be opened from the inside. Advent proclaims the end of religion as such, speaking of a God who must come to us wholly from beyond us.
To retreat into the comfort of religiosity, the smooth apologetic for Christianity that arises from proclaiming homo religiosus (or its more trendy equivalent these days, homo liturgicus) is to retreat from the very hope of Advent itself, the hope against hope that cannot be satisfied by out own designs, but only by the earth-shattering coming of God in Jesus.