There are some demons that will only come out through prayer and fasting. That is why fasting is so important to every Christian.
Satan wants to test and try us, but none of this will prevail with Jesus in our lives. Seek His hand and you shall be protected.
Matthew 17:19-21 (KJV)
19 Then came the disciples to Jesus apart, and said, Why could not we cast him out?
20 And Jesus said unto them, Because of your unbelief: for verily I say unto you, If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you.
21 Howbeit this kind goeth not out but by prayer and fasting.
Luke 4:4-6 (KJV)
6 And the devil said unto him, All this power will I give thee, and the glory of them: for that is delivered unto me; and to whomsoever I will I give it.
7 If thou therefore wilt worship me, all shall be thine.
8 And Jesus answered and said unto him, Get thee behind me, Satan: for it is written, Thou shalt worship the Lord thy God, and him only shalt thou serve.
Lord God, please help us all have a greater desire to commune with You in prayer. May this become a heartfelt thing and not just something we do as a religious ritual. Only by having a real relationship with you, may we truly understand Your will and be drawn to do things that are extraordinary in Your sight. And God, help every Christian understand the need to fast. You were the greatest example of this act and did so for forty days. This, You did, that we may understand the need to fast. You also taught that some demons can only be cast out through prayer and fasting. And as everyone in the faith ought to be ready to fight off the demonic forces, we ought to also fast when needed. And God, You will help us know when this is necessary. Whenever the Holy Spirit is not present, I know that it is important to give you everything, including anything that is holding us back. And often times this takes a lot out of us to change in this way. That is why I am so grateful for fasting and to know that You are working through us in those moments to change us from the inside out. That way, when we come out of our fast, our Spiritual life is renewed and we are made alive again. I know that You have the power to save us all, if we just give ourselves over to You. This I know, as my life has been changed in these moments of fasting. Even many miracles have come of it. I love You Jesus. And I say these things in thy Holy Name. Amen.