Bonhoeffer drew the line in The Cost of Discipleship (1937): cheap grace is the preaching of forgiveness without requiring repentance, baptism without church discipline, communion without confession. It costs nothing because it demands nothing. Costly grace is the treasure hidden in the field for which a person gladly sells all they have — it is costly because it calls us to follow, and grace because it calls us to follow something worth following. The distinction sounds theological but was forged inside a historical catastrophe that exposed what happens when a community receives the benefits of a system without bearing the costs of resisting its pathologies. The Bonhoeffer simulation argues that the structure transfers exactly: AI can be received cheaply (gains without reckoning) or costly (gains with the full weight of moral attention to who bears the costs).
Cheap grace, in Bonhoeffer's account, was destroying the German church from the inside — not through persecution but