Once Peter has been handed the keys to the Kingdom, Jesus harshly-even cruelly, rebukes him for his most understandable response to hearing Christ predict his own horrific suffering, rejection, humiliation and execution. Mark writes that Peter "took him aside and began to rebuke him." We infer that Peter took Jesus away from the other disciples to privately argue with this most appalling prediction.
But Christ chooses to answer Peter publicly, taking the argument back in front of all of the disciples and proceeds to call the man to whom he has just given the Keys to his Kingdom, Satan. "Get thee away from me Satan.." sounds almost vicious until we consider what Jesus-the man-knew and understood, abysmally alone in this knowledge having failed again and again to help his friends see what only he could see.
It seems to me that for those of us who believe in God, Jesus as God is no problem. But we stumble when we consider Jesus the man- "being born in the image and likeness of man, he was known to be of human estate." That's where our minds simply rebel. We tend to focus on Peter when reading and pondering this passage; the man who perhaps reminds us of ourselves with his impetuosity and impulsiveness. And we wince at the harshness of Christ's rebuke, not thinking about the feelings which impelled it.
It is just this humanity which savagely rebukes Peter's typically hasty, volatile response to Christ. We are taught that Jesus willed this passion, this cross. But as we close in on Gethsemane during these forty days of Lent, we can sense the man, his humanity, the awful cost to Jesus through pondering this passage.
"Jesus was no cold Superman, " Guardini writes, " he was more human than any of us. Entirely pure, unweakened by evil, he was open and loving to the core. His ardor, truth, sensitivity, power, capacity for joy and pain were unlimited, and everything that happened to him happened in the immeasurableness of his divinity. What then must have been Jesus' suffering!...
..." Jesus' will to the Passion is not to be broken, but at the thought of it, his whole frame shudders in the grip of unspeakable pain. We feel it in his furious reply to Peter, when the disciple, well meaning but puny of heart, tries to dissuade him..."
"The will to sacrifice stands fast but it has been torn from Jesus' human nature and is throbbingly sensitive; he can bear no tampering with it."