It is written in the Bible that it is good to fast, but I would like to know why. I think it is to learn not to react to what the body demands, as well as to say no to covetousness. Are these the reasons or are there others? I would also like to know some places in the Bible where I can read more on this subject.
ANSWER : PRAYER WTH FASTING
Fasting is an act of great denial. It is also an act of unlimited persuasion and determination, as well as a demonstration of faith that our Father in heaven will perform (beyond a shadow of a doubt) whatsoever the carnal is not able to execute. Prayer with fasting is as if you command the hand of God to accomplish what the Word of God has compelled you to do.
In Daniel chapter 9, we read that Daniel set his face unto the Lord God with prayer and fastings to receive the instructions he needed to accomplish the duties of his calling. In the next chapter, he fasted for 21 days until he was blessed to be in the presence of an angel who brought him the answer straight from God!
While Jesus was on this Earth, He taught his disciples about a devil called lunatic, which could not be cast out of a person except by prayer and fasting. "And when they were come to the multitude, there came to him a certain man, kneeling down to him, and saying, Lord, have mercy on my son: for he is a lunatic, and sore vexed: for ofttimes he falleth into the fire, and oft into the water. And I brought him to thy disciples, and they could not cure him. Then Jesus answered and said, O faithless and perverse generation, how long shall I be with you? how long shall I suffer you? bring him hither to me. And Jesus rebuked the devil; and he departed out of him: and the child was cured from that very hour. Then came the disciples to Jesus apart, and said, Why could not we cast him out? 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. Howbeit this kind goeth not out but by prayer and fasting." Matthew 17: 14 - 21.
Giving no offence in any thing, that the ministry be not blamed: But in all things approving ourselves as the ministers of God, in much patience, in afflictions, in necessities, in distresses, in stripes, in imprisonments, in tumults, in labours, in watchings, in fastings; By pureness, by knowledge, by longsuffering, by kindness, by the Holy Ghost, by love unfeigned, by the word of truth, by the power of God, by the armour of righteousness on the right hand and on the left, by honour and dishonour, by evil report and good report: as deceivers, and yet true; As unknown, and yet well known; as dying, and, behold, we live; as chastened, and not killed; As sorrowful, yet alway rejoicing; as poor, yet making many rich; as having nothing, and yet possessing all things. 2 Corinthians 6: 3 - 10. Paul greatly exposed what it would take to save a soul, including a list of things we need to do so the ministry not be blamed for the loss of souls. I have been careful to be ready at all times to execute any one of these things, or as many as necessary. Fasting alone is not the answer. It must be accompanied with what you read in these verses, much like faith without works is a dead thing.
I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service. And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God. Romans 12: 1 - 2. We are compelled to be transformed by the renewing of our mind in order to know what is the good and acceptable will of God. Fasting your food and your sleep is a great way to renew your mind as you read your Bible with a hunger to receive from God the direction the Holy Ghost has for you to see. There are 1,001 things in this world that can distract you. When your body becomes weak from the lack of food, this weakness becomes a real strength that gives you an unlimited determination to go all the way. At the end of your fast, you walk away with the revelation of how to conquer the carnal mind.
I have been walking for 30 years with nothing but the perfect will of God, doing those things which are acceptable unto Him. This comes only through reading the Word of God. As you read the Word of God, you will begin to walk the same way. Hallelujah!