People naturally want to pray and fast when they desire getting closer to God. This is mostly because we as humans feel inadequate to be close to our heavenly father due to the inward guilt we have concerning our sin. So to satisfy this inadequacy we chose to deny ourselves in order to become more pure. Surprisingly, the true purpose of fasting is the same reason.
Fasting is to deprive ones flesh (body) while focusing on the inward man, the spirit. When you choose to shut down your flesh you will shut down Satan. This is not to suggest our flesh is Satan, however Satan can only get to us through the flesh, because he only has power in the material realm.
Ways Satan works against us.
1. His attacks are only through the material realm.
He has no power in the spiritual realm. He has been stripped of all spiritual power by Jesus Christ, Colossians 2:15. He can however attack us through the mental realm. There are two parts to our mind, the flesh of the mind and the spirit of the mind. The flesh of our mind is where we have the greatest battles because it being a part of our flesh, Satan and demonic powers can attack and influence here, Colossians 2:18; Ephesians 4;17-19. The only power Satan has is through seduction and manipulation of the flesh, which includes the mental, emotional, and physical body.
2. He is always searching for ways to destroy us, 1st Peter 5:8.
All the demonic world wants God's creation destroyed. For this reason Satan is roaming to and fro upon the earth trying to finds ways to carry out his evil, Job 1:7 and 2:2.
3. He comes to steal, kill, and destroy.
John 10:10 shows us that Satan's greatest desire is to steal all he can, kill everyone, and destroy that which God has created and doing upon the earth. But we can rejoice because the Bible teaches us that Jesus came to destroy the works of the devil, 1st John 3:8; Romans 16:20; Hebrew 2:14.
Because these things exist in the material realm, it is necessary for us to do things that help us to remain in faith and walk in the spirit.
1st Peter 5:6-9
Therefore humble yourselves under the mighty hand of God, that He may exalt you in due time, casting all your care upon him, for he cares for you. Be sober, be vigilant: because your adversary the devil walks about like a roaring lion, seeking whom he may devour. Resist him steadfast in the faith, knowing that the same sufferings are experienced by your brotherhood in the world.
One of the best ways to humble yourself before the Lord is fast and pray. When you are facing something and you want to work through it, the more you pray and fast, the more you will reach your desired purpose. The less you depend upon your flesh and the more you depend upon the power of God in you, the more successful you will be in your Christian walk, 2nd Corinthians 12:9,10.
Fasting is denying your flesh and concentrating upon your spirit in God.
This allows you opportunity to do the works of Jesus Christ.
Jesus' disciples learned this when the asked Jesus why they could not cure a man's son of the evil spirit that was upon him. Jesus replied that "this is done by prayer and fasting. Read Matthew 17:14-21 for the story.
So what type fasting will God accept?
Isaiah 58:1-11 shows the type fasting that God accepts. Israel was fasting for all the wrong reasons so God used the prophet Isaiah to show them what he would allow.
Verse 6: The fast that God chooses is one where:
1. The bonds of wickedness are loosed.
2. Burdens are undone.
3. The oppressed are made free.
4. The heavy yoke is broken.
What this means is fasting should be done so that you can better do the work of God as Jesus expressed he was here to do in Luke 4:18,19.
So pray and fast. Do it often, but do it unto the Lord.