Peter, drawing from his own experience of failing to watch, pray, and falling into temptation by denying Jesus, exhorts Christians to be self-controlled, alert, and firm in faith. He warns that the devil prowls like a roaring lion, seeking to devour believers. The devil's tactics include insinuating doubt, spreading heresy, sowing discord, and displacing the centrality of Jesus Christ. To resist the devil, believers must keep their faith in God's promises, commands, and person, remaining vigilant and aware of the enemy's schemes.

Be self-controlled and alert. Your enemy the devil prowls around like a roaring lion, looking for someone to devour. Resist him, standing firm in the faith, because you know that your brothers throughout the world are undergoing the same kind of sufferings. Now remember who it is that is telling us this. And who is it? Peter, of course. And what is there in Peter's background that makes this something to be underlined? In the 14th chapter of the Gospel according to Mark, and remember behind Mark the author there stands the strong personality of Peter who is dictating his reminiscences of his life with Jesus. In the Gospel of Mark, remembering that it's dictated to Mark by Peter for the most part, the words of Jesus are recorded. Watch and pray, lest you enter into temptation. And before the 14th chapter of Mark is over, we have that shameful episode where a Peter who failed to watch, a Peter who failed to pray, fell into temptation and denied his Lord not only once, but again and again. It's out of that kind of experience that Peter now tells other Christians, be alert, be self-controlled, keep a firm grip on yourself, have the eyes of your understanding wide open to the risks and the dangers in a non-Christian world. I failed to watch, I failed to pray, I fell into temptation and denied my Lord, and now out of that bitter experience, I am telling you, be self-controlled, beyond the alert, because your enemy the devil prowls around like a roaring lion looking for someone to devour. So the exhortation of Peter is not some abstract advice, it comes out of his own personal experience. He encourages us to do what he failed to do, and for that, he experienced heart-breaking repentance. So he says, be self-controlled, keep a firm grip on yourself, and be alert, have the eyes of your understanding wide open to the dangers that you face in a non-Christian world. Remember that the enemy, who sometimes masquerades as an angel of plight, also prowls around like a roaring lion looking for someone to devour. Resist him. Resist him, standing firm in the faith. Now what does the devil do? Let me suggest that according to the scriptures, there are several things that he does and does with a great deal of expertise. First, he loves to insinuate doubt. Isn't that the way that he approached Lady Eve? Has God really said that something terrible will happen to you if you disobey? In other words, doubt what God said. And that is where it always begins. Doubt concerning what God has revealed in his word. To insinuate doubt in the mind is the beginning of the driving of the wedge to separate us from God. Then there is the spread of heresy. You begin by denying or doubting the authority of the Bible, and then you begin to be fascinated by weird ideas and deviations from sound doctrine. The third tactic of the devil is to sow discord. For he knows that if Christians remain together, they can encourage one another in fighting the enemy. But if he can divide, he can more easily conquer. Divisions in churches among those who claim to believe in the same Lord, those divisions are works of the devil. For the devil not only insinuates doubt and encourages deviation from sound doctrine, but he sows the tares of discord among the weak in the field of God. And if there is anything that the devil loves to do more than all of these, it is to displace the centrality of Jesus Christ. If he can get the eyes of our faith off of Jesus and onto something else, he's already three-quarters of the way onto victory. We must behold no man save Jesus only. To keep the eyes of faith fixed on him, that is the way to resist the devil. Notice that Peter says that we stand firm and we resist the devil in the faith. What does that mean? It means that when the enemy would insinuate doubt, we keep on believing the promises of God. We keep on taking seriously the commands and the warnings of God. We remain bound to him by faith in his promises, in his precepts, and in his person. Well, that is, of course, the statement of Jesus to Peter, who was advising him that there might be a way to glory without going the route of the cross, and our Lord would have nothing at all to do with a deviation from his Father's will. So, we can resist the devil, according to Peter, if we have our eyes wide open to the dangers that we face, and if we are onto the devices of the devil. As Paul puts it, we are not ignorant of his devices, of his mode of operation, of his tactics and his strategies. We will fight doubt. We will refuse to deviate from sound doctrine. We will be onto him when he seeks to sow discord among brothers and sisters.