In both Mark 8:31-33 and Matthew 16:21-23, Jesus predicts His death and resurrection. Peter protests, and Jesus says to him, “Get thee behind me, Satan!” I understand that Jesus calls Peter “Satan” because he’s trying to go against God’s plan. But why does Jesus say “Get behind me”?
Because Peter is “standing in the way” of the path the Jesus must follow. “Get behind me” indicates “don’t stand in front of me blocking the path.”
It should be noted that, in these passages, the allusion that Jesus makes is not necessarily to the Christain notion of the fallen-angel-tempter-into-sin, but to the older Jewish idea of the one who acts as God’s agent in testing the faith of another (as God used Satan to test Job). In the first century, both concepts of Satan were prevalent, so it is not that they are mutually exclusive, of course.
Since Tom has answered the question, I’ll tell a joke:
Grim
" Get thee behind me Satan…and don’t push!"
Buckwheat said that.