A powerful Good Friday devotion would be to read Article VIII of the Formula of Concord: “The Person of Christ.” It will help you to appreciate even more the magnitude of what happened on the Cross.
Luther’s dispute with Zwingli went beyond their disagreement over Holy Communion and whether “this is my body” is a fact or a figure of speech. They had different understandings of Christ.
This question arose: Can we say that on the Cross “God suffered” or “God died”? No, said Zwingli. God is “impassible.” He cannot suffer or die. Christ has both a divine and a human nature. So on the Cross only His human nature suffered. Zwingli dismissed scriptural language to the contrary as, again, a figure of speech.
Luther said that while it is true that God, in Himself, does not suffer or die, in Christ something else is going on. In taking on human nature, God the Son could experience what human beings experience. By virtue of the incarnation, the unity of the Trinity, the communication of the attributes, and the personal union of Christ’s two natures, we can say that God suffered and died.
Later, Chemnitz would explain it using this analogy (and it is only an imperfect analogy, since the Son of God was not simply a deity in a human body, but rather took on a human soul as well): A human being has a spiritual and a physical nature. If you cut your finger, it isn’t just your body that suffers. You suffer because your two natures come together in your person.
After the jump, read how this is treated in one of the key confessional documents of Lutheran theology. I know I trot this out every few years around this time, but it bears repeating.
For one thing, to believe that God suffered and God died helps us to understand the atonement more deeply. It isn’t God punishing his kid for what other people did, as mockers and some liberals are saying today. In the atonement, the Second Person of the Trinity sacrificed Himself for sinful human beings. And in doing so, He took into Himself, by His omnipotence, the world’s evil and the world’s suffering, our “iniquities” and “transgressions” and our “griefs” and “sorrows” (Isaiah 53, a major passage of Scripture to read for today). And this has a bearing on the problem of evil and the problem of pain, since we know that, far from looking down on the evils and sufferings of the world and doing nothing, God took them into Himself in His redemption of the world.
Illustration: The Isenheim Altarpiece by Matthias Grünewald. [Public domain], from Wikimedia Commons. Originally at the Hospital of St. Anthony, where plague victims could contemplate Christ, depicted as bearing their disease.