Without using what God provided for our protection, we will fail. You are of God, little children, and have overcome them, because He who is in you is greater than he who is in the world. And they overcame him by the blood of the Lamb and by the word of their testimony, and they did not love their lives to the death. In this spiritual conflict we must be committed to Jesus, no matter what the cost. If the devil can get us to operate in fear or doubt, he gains the advantage over us.
Authority is exercised by spoken words.