Lord, even the demons are submitting to us in your name.
LUKE 10:17

The disciples of the Lord after returning from ministering to the sick in the name of Jesus reported with excitement and amazement that even the [evil menacing, lords of darkness, terrifying] demons are obeying there every command.
You see, every believer can cast out demons. Though there is a special ministry of deliverance as well as every believer should spread the gospel but there is a special ministry of spreading the gospel,the evangelist ministry.
The problem is:

1.Some believers love walking in darkness. And walking in darkness is walking in the territory where the devil is Lord{Submit yourselves to God, and then resist the devil,and he will run away from you terrified }

2.Some don't believe that it is their Sonship right to do that. For the word of God works [effectively] to those who believe.

3.The neglect of spending time with the Lord.
The apostles of then said they would give themselves to prayer and the ministry of word.
Many get that statement wrong, thinking they meant they would give themselves to praying and preaching the word of God.
Nope.
What they meant was that they will keep talking to God consistently and feeding on His word consistently.
Leave the practice of the presence of God, and see how dry you will be?
Many are cold because of this.