A Successful Break-In

A farm where I traveled yesterday to buy fresh picked corn and other vegetables.
I've been meditating on Luke 12:35-48 that is mainly about readiness for Christ's coming.  I had not been finding it very nourishing.  Then in Gerhard Lohfink's Jesus of Nazareth: Who He Was, What He Wanted, which I have been reading for several weeks, I came to his treatment of just one of the verses in this passage from Luke. 
Lohfink focuses only on verse 12:39: "If the owner of the house had known at what hour the thief was coming, he would not have let his house be broken into."  He suggests that it is "not a warning against a future break-in but is looking back at one that has already happened....The successful break-in would then be the coming of the reign of God, and the text would say: the reign of God has already come."  In Jesus Christ God's Rule has already broken into our world, dug its way through our hardened mud walls.
He says that Jesus broke into the spaces of the old society, "the taken for granted things from which people interested only in themselves build the houses of their lives."  The old society would have defended itself, but Jesus came like a thief in the night, unexpected.  "With him the reign of God was suddenly there, and the new had already begun--in the midst of the old world."  A successful break-in!
I found this oddly comforting.  I have often been satisfied with the ambiguity of the already-but-not-yet coming of the Lord as we find it in the New Testament.  But I was deeply stirred by this notion of the reign of God as an already successful break-in.