Lord, even the demons are subject to us in Your name
It was an eye-opening experience for the disciples to discover that the demons were subject to them in Jesus' name. Subject ( hupotasso ) is a military term meaning "to arrange under." It pictures a group of soldiers snapping to attention and following precisely the orders of their commanding officer.
Perhaps the disciples suffered under the same misconception which blinds many Christians today. We see God and His kingdom on one side and Satan and his kingdom on the other side. Both kingdoms seem to be very powerful, and here we are, stuck in the middle between the two, like the rope in a tug of war. On some days God seems to be winning and on other days the devil appears to have the upper hand. And we don't seem to have anything to say about who wins the battle.
But the disciples came back from their mission with a new perspective, a true perspective. Spiritual authority is not a tug of war on a horizontal plane; it is a vertical chain of command. Jesus Christ has all authority in heaven and on earth (Matthew 28:18); He's at the top. He has given His authority and power to His servants to be exercised in His name (Luke 10:17); we're underneath Him. And Satan and his demons? They're at the bottom, subject to the authority Christ has invested in us.
Why, then, does the kingdom of darkness exert such negative influence in the world and in the lives of Christians? In a word, the lie. Satan is not an equal power with God; he is a vanquished foe. But if he can deceive you into believing that he has more power and authority than you do, you will live as if he does! You have been given authority over the kingdom of darkness, but if you don't believe it and exercise it, it's as if you didn't have it.
Authority is the right to rule based on position. You have the authority to do the will of God because of your position in Christ. It's an authority you could never have independent of God, so you need to remain dependent on Him to live victoriously.