Like the apostle Paul, Dietrich Bonhoeffer is so right on about grace and its relationship to the following of Jesus, that it's scary. Sometimes his initial impact on the Protestant mind feels like a threat to the sovereignty of God, just as the same impact on an Orthodox mind seems a threat to the protocols of worship of the divine splendor.
When I first encountered the book Cost of Discipleship the intensity of its light and heat was too much for me: I wanted to crawl back into my Christian cave and hole up there, happy to be enlightened by the little fragments of sparkly truth I had cherry-picked from the eternal fire. But little by little, pretending to follow Jesus, I got braver, and cautiously emerged from my cozy Christianity with all its doctrinal and dogmatic assurances, until I was fully exposed to what Bonhoeffer was pointing out to me.
It takes real guts to stand beside, and then to follow behind, the Son of God, and, asking no more questions of Him, to just do what you see Him doing, to let Him lead you in the dance to Calvary, for all the world, then, becomes for you what it was and is for Him: infinite hunger and thirst for salvation crying out, inexhaustible holy and divine bread and wine of sacrifice raining down as manna first, then as quails, and you partitioned between earth and heaven, but not divided.
You realise that following Him, you too can be Christ. No, that you must be. There is no higher way above, nor safer road below, than that of the holy cross: this is the cost of discipleship.