What is the purpose of prayer and fasting in the dispensation of grace?

I have been a Christian for a while, and have recently learned about dispensationalism and grace. God wants me to pray and fast to get rid of unbelief. However, prayer and fasting has become a stumbling block to me because of wrong teaching. Please help me to understand prayer and fasting in this dispensation of grace.

Do I have to read the word when I pray and fast? Is this commanded in order for me to get rid of unbelief through prayer and fasting. (i.e. like 1 hour for breakfast; 1 hour for lunch, etc.) Do I have to give alms when I pray and fast? Is fasting just abstaining from food, or food and water? Can I watch TV when praying and fasting.

Fasting has become legalistic for me, and I get really tired from the way I have been doing it through reading for hours from the word of God, interceding for others in prayer, and not eating food and drinking water. Please help me to know the truth about prayer and fasting.

I got your question and can see your sincerity.  However I would like you to first consider these things about fasting.

Fasting was never a commandment of God, even under the law (except on the day of atonement).

Fasting is a choice of a person who is so engrossed with a spiritual need that they would choose rather than eating to spend the time in God’s word and prayer.

It is never so that God would do something, but that we would do something.

Those who think that God will answer their prayers if they can prove to him their sincerity or who think that by their much praying God will hear them are practicing paganism (Matthew 6:7).

The purpose of prayer is fellowship with God. Praying in the Spirit is praying in accordance to God’s word and will as revealed in the Bible.

Prayer is for peace and encouragement in doing those thing God would have us do (Philippians 4:5-13). 

So, prayer and fasting is not for the purpose of getting rid of unbelief.  Romans 10:17 says that faith cometh by hearing and hearing by the Word of God.  You get rid of unbelief by reading and believing what God said – particularly what God says to us in this age of grace.

Since fasting is not a command, there are no regulations requiring alms, or water, or even TV.  There is no requirements even to fast.

Rejoice in God’s acceptance of you in Christ, by grace, through the cross.  Then live for him!