I have given you authority over all the power of the evil one; nothing will harm you. (Luke 10:19)
This is an extraordinary promise, and, believing it, and acting on it, would completely transform the life of a Christian. When we think of how easy it was for Satan to deceive our first parents with his lies, and deceit, and now we know that Jesus is giving us full authority over Satan, this must surely be a complete reversal of the evils of Original Sin.
Notice that Jesus is saying "I have given you…" In other words, this is not some promise to be fulfilled in the future. This authority has already been given to us. If Jesus gives us this authority, it is so that it be used. If we want nothing to harm us, then we have to exercise that authority. It is important that we use this authority wisely and correctly. It is not something that can be flaunted, and exercised as a magical power. Satan would be very pleased if we did this, because we would be acting as if the power was our own.
Of ourselves we have absolutely no power over Satan, and, while we might forget that, Satan certainly doesn't. This power is pure gift, and it can only be used with humility and gratitude. I can use it firmly, of course, as long as I remember that I am using the power of Jesus, with his specific permission. Any confidence I have in using this power stems directly from the fact that I take this promise of Jesus seriously. It is extraordinary that Jesus should choose to let us share his power, but that's what he has chosen to do.
A very important part of the ministry of Jesus was driving out demons who had taken over within someone. Jesus was very definite in letting Satan know that he had come to put him in his place. Satan tested Jesus right from the start (see Luke 4:1-13) because, like any bully, he was terrified of being challenged. Satan spoke through people, including Peter (see Mark 8:33), and he did everything in his power to thwart the plans of Jesus.
From the time I was a child, I always got a great kick out of seeing a bully getting his comeuppance. Satan had it his own way for too long. Indeed, in today's world, he seems to be having a field day. The human heart is made in such a way that it yearns for the spiritual. When the Spirit of God is absent, the evil one takes over. There is always some spirit speaking to me at any one time. It is either the Holy Spirit, the human spirit, or the evil spirit.
Discernment is a gift of the Holy Spirit that enables me discern the spirits. Jesus told us to "watch and pray" (cf. Mark 14:34). It is not enough to pray. Satan is also listening when I pray, and he is always ready to thwart my every effort at doing the good. It is vital that I accept the authority that Jesus offers me in this promise, and to use this authority wisely, firmly, and constantly.
This is a prayer that should constantly be on my lips: I use the power, authority, and precious Blood of Jesus, and I bind in his name every presence and influence of Satan within me. In the name of Jesus, and through the authority he has entrusted to me, I command you, Satan, to depart from me, to go to Jesus, and let him dispose of you in whatever way he chooses. When I speak of exercising this authority, I am not speaking of exorcism. It is nothing that dramatic. When I find myself drawn towards some situation, action, or train of thought that does not lead to my good, I can exercise the authority, and discover that I become free from the bind.
Using this authority means freedom from bondage. I know of recovering alcoholics who use this authority over the demon drink. When I constantly exercise this power that is entrusted to me, I become more and more aware of exactly what it means. It is only through exercising this authority that I come to fully appreciate just how important and powerful it is. For those who do not understand, no words are possible, and for those who understand, no words are necessary.
St. Peter tells us to stand up to Satan, and, because he is a bully, he will run from us, if we are strong in our faith (cf. 1 Peter 5:9). Without claiming any special knowledge, it is my experience that this authority is not exercised to any great extent. That is a great pity, and Satan is the only one who benefits from this. I can sprinkle myself with holy water, wear a religious object, or have religious artifacts in my home, but if I do not do this with authority, with boldness, and with expectation, then I am not exercising my authority.
Jesus is the model for all our actions. He asks us to follow him, to imitate him, to do as he did. It makes an enormous difference in the life of a Christian when this promise is fully accepted, and firmly acted on. If I don't accept this power, I do not have it. If I accept it, I must use it, and only then will I appreciate the strength that is mine because of the promises and the power of Jesus.