He then began explaining things to them: "It is necessary that the Son of Man proceed to an ordeal of suffering, be tried, and after three days rise up alive." He said this simply and clearly so they couldn't miss it. But Peter grabbed him in protest. Turning and seeing his disciples wavering, wondering what to believe, Jesus confronted Peter. "Peter, get out of my way! Satan, got lost! You have no idea how God works." Mark 8:31, Message.
The proud Peter got it right between the eyes. He was sincere enough, but had hit the most sensitive nerve ending in Jesus' being. The forcefulness of His rebuke to Peter implies the importance of the cross to His ministry and the need to educate the future leaders of His church on its centrality.
Not only had the temptation come, but it had emerged from the mouth of a friend. It is a sad fact of life that Satan can use Jesus' followers--even His ministers--to do his own work.
As Christians we have not only the potential of betraying Jesus, but also one another. We too can guide fellow Christians in the wrong direction and discourage them from doing God's will by advising them to avoid all dangers to themselves and inconveniences to ourselves. Lest we unwillingly play the role of Satan, we need to be more aware than was Peter.
Peter's experience can teach us yet other lessons. One is that we as Christians are a mixed bag. In one moment I can have a divine insight, then in the next I can be a tool of the devil. At our best we are fallible creatures partly controlled by knowledge and partly by ignorance. All of us have one foot in the kingdom. We have been saved in the sense that we have accepted Jesus, but the plain fact is that He has a lot more to do in us.
Another lesson is that we need to be careful not to cast off people because of their stupidity and errors. Jesus, in the days and weeks to come, would demonstrate almost infinite patience in working with His erring disciples. One writer has pointed out that "only a massive stupidity could keep them from understanding," but they managed to do exactly that until after the Resurrection. Jesus, however, did not abandon them as a lost cause. Our Savior had begun to teach them about the meaning of being the Christ. Just as He didn't give up on them, so He hasn't given up on me. And I shouldn't give up on you.