God was performing extraordinary miracles by the hands of Paul, so that handkerchiefs or aprons were even carried from his body to the sick, and the diseases left them and the evil spirits went out.
But also some of the Jewish exorcists, who went from place to place, attempted to name over those who had the evil spirits the name of the Lord Jesus, saying, “I adjure you by Jesus whom Paul preaches.” Seven sons of one Sceva, a Jewish chief priest, were doing this. And the evil spirit answered and said to them, “I recognize Jesus, and I know about Paul, but who are you?” And the man, in whom was the evil spirit, leaped on them and subdued all of them and overpowered them, so that they fled out of that house naked and wounded.
To fight the good fight of faith, one must be a true follower of Jesus, filled with the Spirit of God and prepared to do battle. If not, we enter into this spiritual battle on our own folly and risk the injury of Acts 19:16. The evil at hand must recognize Jesus in you for it to yield to the words you speak!
As a believer though, we need not fear the enemy, but simply engage it. The name of Jesus, used by the true believer, is the power feared by the enemy. The enemy must obey. The battle is won by Jesus, but it costs us something; energy and some emotional pain; thus we must renew our strength and reconnect to God in prayer. Jesus does this several times in the gospels, most notably in Matthew 14:23, Mark 6:46 and Luke 5:16.
The perils of post-spiritual warfare is simply more spiritual warfare. The enemy is insidious, always looking for your weakness to to exploit you, especially if you are engaging him. Thus right after an engagement, we must look to God in prayer, seeking protection, strength, insight and renewed strength. I believe this is what Jesus did when he went to the mountain to be with the Father.
Our biggest mistake as Christians in a modern world is first to ignore the spiritual battle, but second, to engage the enemy thinking that there will be no cost. This attitude can only be describe as flippant and careless. Those who are not prepared for the battle are always injured, sometimes they are so psychologically wounded that they never quite recover. The Christian must be prepared for the battle and the toll. It is only then that we can continue to engage in spiritual warfare and live the victorious life God has for us.
Be prepared friends, its coming.