Satan is a formidable enemy, to be sure, but in a personal sense, he is not as directly dangerous to us as the world or our own human nature. The chances of him confronting us individually are small in comparison to the influences of our ever-present hearts and the world in which we conduct our lives. Certainly, as our Adversary, he "walks about like a roaring lion, seeking whom he may devour" (I Peter 5:8), but unlike God, he is not omniscient. While he can be only at one place at one time, he has many assistants.
We are far more likely to be confronted by one of his demon assistants than the Adversary himself, which is bad enough. However, he and his demons have constructed attitudes, institutions, systems, and entertainments into the course of this world, which they effectively use against us, even when they are absent from the scene. Most of their evil influence comes from the system.
We need to remember, though, that God has put a wall of protection around us, so demons can go only so far in their attempts to corrupt us and destroy our loyalty to God and His truth (Job 1:6-10). Their major responsibility before God at this time appears to be to provide tests for us to meet and overcome, in the same way God used Satan to test Job and to tempt Christ (Matthew 4; Luke 4). In this respect, they play a large role in helping us to recognize evil.
God gives us advice regarding them in I Peter 5:8-9: "Be sober, be vigilant; because your adversary the devil walks about like a roaring lion, seeking whom he may devour. Resist him, steadfast in the faith, knowing that the same sufferings are experienced by your brotherhood in the world." In essence, His advice is, "Be self-controlled, be alert, and resist him!" Peter's first term, "be sober," urges us not to let fear of him fluster us to the point that we cannot think clearly. The second term, "be vigilant," charges us to be fully awake, to set ourselves in a state of watchfulness and readiness. The third term, "resist him," is a command not to turn and run but to stand firm.
This instruction lets us know that Satan is not all-powerful. With the protections God provides, including His continuous presence and alert regard for His children, Satan can be beaten. The same Jesus who has already defeated Satan is on His throne, overseeing our well-being. His protection is not something we flaunt, but is power we can rely on.
James 4:7 adds additional advice: "Therefore submit to God. Resist the devil and he will flee from you." Again, the charge is to resist, but it is directly coupled with submission to God. Submission is the voluntarily act of placing oneself under the authority of another to show respect and give obedience. If we submit to God, Satan will flee.
Ephesians 6:11 parallels the other two instructions. "Put on the whole armor of God, that you may be able to stand against the wiles of the devil." "Stand against" is yet another way of saying "resist him." "Stand" in the Greek indicates that one must hold fast a critical position as an army must do in warfare. However, it is not a passive term, describing something like an unmoving brick wall, but an aggressive, attacking term. In other words, we are to hold the ground we have already gained by going forward.
How, then, do we resist? How do we hold our ground by going on the offensive? We must return in thought to I Peter 5:9, where the first phrase is better translated as, "Resist him, standing firm [or solid] in the faith." Putting this into military terms, a soldier would be likely commanded, "Do not surrender! Do not give up any ground! Do not back down! Move forward with all you've got! Reinforcements are right behind you."
We have the God-backed promise that Satan will flee! Who can resist God's will? The key words here are "standing firm" and "faith." "Standing firm" or "solid" is used in the sense of "unmovable." When linked with faith in practical terms, it means we are absolutely sure or immovably convicted in the face of a strong test.
Overall, the apostles' instruction suggests that what we experience vis-à-vis Satan is common to this way of life. Their advice does not say that he will flee immediately, but flee he will. As used here, "faith" can be understood as either a personal trust in God or confidence in Christian doctrine, as either one fits the context. Ultimately, if we use our relationship with God properly, the confidence in Christian doctrine becomes trust in God Himself.