To be sober and vigilant are compatible actions. They go together. Peter used them here to urge Christians to be alert to present danger. A Present Enemy. The Bible pictures the devil as a present enemy.
Christians are to recognize the devil as their adversary or enemy.
A Powerful Enemy. Because the devil is a powerful enemy, we must learn to recognize him in his approach. Though the devil is a powerful enemy, he is not all-powerful or omnipotent as God is. Neither is he omniscient or omnipresent as God is. That he is able to influence Christians is evident from this passage in I Peter.