“Get thee behind me, Satan: for thou savourest not the things that be of God, but the things that be of men” (Mark:8:33). What was it that so roused our Lord? The very snare to which we are all so exposed: the desire of saving self; the preference of an easy path to the cross. Is it not true that we naturally like to escape trial, shame, and rejection; that we shrink from the suffering which doing God’s will, in such a world as this, must ever entail; that we prefer to have a quiet, respectable path in the earth—in short, the best of both worlds? How easily one may be ensnared into this! Peter could not understand why the Messiah should go through all this path of sorrow. Had we been there, we might have said or thought yet worse. Peter’s remonstrance was not without strong human affection. He heartily loved the Savior too. But, unknown to himself, there was the unjudged spirit of the world.
—William Kelly, quoted in William MacDonald’s, The Believer’s Bible Commentary