I ran across this great quotation from Calvin’s commentaries in preparation for my sermon tomorrow. I just had to share it. The reasoning is amazing.
What is Satan but God’s executioner to punish man’s ingratitude? This is implied in Paul’s language, when he represents the success of Satan as confined to unbelievers; for the children of God are thus exempted from his power. If this be true, it follows that Satan does nothing but under the control of a superior: and that he is not (αὐτoκράτωρ) an unlimited monarch.