Bill Bright the passionate leader of Campus Crusade (CRU) had a power experience with God in the late 1990's specifically around this area of fasting. Read his fasting testimony and allow God to speak to you through it.
"I believe the power of fasting as it relates to prayer is the spiritual atomic bomb that our Lord has given us to destroy the strongholds of evil and usher in a great revival and spiritual harvest around the world.
Increasingly I have been gripped with a growing sense of urgency to call upon God to send revival to our beloved country. In the spring and summer of 1994, I had a growing conviction that God wanted me to fast and pray for forty days for revival in America and for the fulfillment of the Great Commission in obedience to our Lord's command.
At first I questioned, "Is this truly God's call for me?" Forty days was a long time to go without solid food. But with each passing day, His call grew stronger and more clear. Finally, I was convinced. God was calling me to fast, and He would not make such a call without a specific reason or purpose. With this conviction, I entered my fast with excitement and expectancy mounting in my heart, praying, "Lord, what do you want me to do?"
I believe such a long fast was a sovereign call of God because of the magnitude of the sins of America and of the Church. The Lord impressed that upon my heart, as well as the urgent need to help accelerate the fulfillment of the Great Commission in this generation.
As I began my fast, I was not sure I could continue for forty days. But my confidence was in the Lord to help me. Each day His presence encouraged me to continue. The longer I fasted, the more I sensed the presence of the Lord. The Holy Spirit refreshed my soul and spirit, and I experienced the joy of the Lord as seldom before. Biblical truths leaped at me from the pages of God's Word. My faith soared as I humbled myself and cried out to God and rejoiced in His presence.
This proved to be the most important forty days of my life. As I waited upon the Lord, the Holy Spirit gave me the assurance that America and much of the world will, before the end of the year 2000, experience a great spiritual awakening. This divine visit from heaven will kindle the greatest spiritual harvest in the history of the Church. But before God comes in revival power, the Holy Spirit will call millions of God's people to repent, fast, and pray in the spirit of 2 Chronicles 7:14: "If my people, who are called by my name, will humble themselves and pray and seek my face and turn from their wicked ways, then I will hear from heaven and will forgive their sin and will heal their land."
The scope of this revival depends on how believers in America and the rest of the world respond to this call. I have spent fifty years studying God's Word and listening to His voice, and His message could not have been more clear." HT
For more on this subject download Bill Bright's 7 Basic Steps to Successful Fasting and Prayer