From the Preface to Gerhard O. Forde's On Being a Theologian of the Cross: Reflections on Luther's Heidelberg Disputation, 1518:
A theologian of the cross, Luther says, looks at all things through suffering and the cross. It is also certainly true that in Christ God enters into our suffering and death. But in a theology of the cross it is soon apparent that we cannot ignore the fact that suffering comes about because we are at odds with God and are trying to rush headlong into some sort of cozy identification with him. God and his Christ, Luther will be concerned to point out, are the operators in the matter, not the ones operated upon (thesis 27, Heidelberg Disputation). In the gospel of John, Jesus is concerned to point out that no one takes his life from him but that he lays it down of his own accord (John 10:18). In the end, Jesus suffers and dies because nobody identified with him. The people cried, "Crucify him!" One of his disciples betrayed him, another denied him, the rest forsook him and fled. He died alone, forsaken even by God.
Now we in turn suffer the absolute and unconditional working of God upon us. It is a suffering because as old beings we cannot abide such working. We are rendered passive by the divine activity. "Passive," it should be remembered here, comes from the same root as "passion," which is, of course, "to suffer." And so we look on the world anew in the light of Christ's Passion, "through suffering and the cross" (thesis 20), as ones who suffer the sovereign working of God. A sentimentalized theology gives the impression that God in Christ comes to join us in our battle against some unknown enemy, is victimized, and suffers just like us. Like the daughters of Jerusalem we sympathize with him. A true theology of the cross places radical question marks over against sentimentality of that sort. "Weep not for me," Jesus said, "but for yourselves and for your children."