Carl Truman on Martin Luther’s forgotten insight :
At the heart of this new theology was the notion that God reveals himself under his opposite; or, to express this another way, God achieves his intended purposes by doing the exact opposite of that which humans might expect. The supreme example of this is the cross itself: God triumphs over sin and evil by allowing sin and evil to triumph (apparently) over him. His real strength is demonstrated through apparent weakness. This was the way a theologian of the cross thought about God.
The opposite to this was the theologian of glory. In simple terms, the theologian of glory assumed that there was basic continuity between the way the world is and the way God is: if strength is demonstrated through raw power on earth, then God’s strength must be the same, only extended to infinity. To such a theologian, the cross is simply foolishness, a piece of nonsense.
Now, some will respond: But the theology of the cross has not been forgotten; it is often talked about and discussed and even preached. But here’s the rub: in the Heidelberg Disputation Luther actually refers not to a theology of the cross but to theologians of the cross, underscoring the idea that he is not talking about some abstract theological technique or process but rather a personal, existential, real way that real flesh-and-blood theologians thought about, and related to, God. A person’s theology, whether true or false, good or bad, is inseparable from the individual’s personal faith.