In Mark 8.31-33, Jesus rebuked Peter, because he disrespected the word that was spoken concerning death on the cross. Peter loved the Lord and meant well; but being overly concerned that caused him to reject the word spoken by Christ and viewing it as not making any sense. Peter couldn’t imagine Jesus being arrested, abused and killed by wicked men. “No, Lord, he said; this won’t happen to you.”
Jesus was highly offended that Peter would question His authority. Jesus called Peter, Satan and said he only respected men and not God. The lesson is to accept what God said. It might appear questionable; but accept it. Don’t question that He doesn’t know what He is talking about; because that is what Peter did.
Jesus said, the words He speaks are spirit and they are life. John 6.63