Prayer Sometimes Involves Fasting
"They were worshipping the Lord and fasting" (Acts 13:2).
Fasting is an outward means of demonstrating humility and an outward manifestation of inward change. The biblical record reflects fasting in crisis, in repentance, in selection and commissioning of church leaders, as a regular discipline, and for other reasons (mourning, seeking to understand a perplexing vision, consecration, focus/preparation).
It's a spiritual discipline that Jesus practiced and God honors. If He commanded His chosen people to turn from rebellion and return to Him in fasting, might He not also ask the same of us? Keep in mind that fasting is not optional. In Matthew 6:16 Jesus did not say if you fast, but rather when you fast. It's a command, but we need to do it for the right reasons.
Fasting disciplines our bodies. When we fail such discipline, sin often results. Submitting to every craving may make us sluggish and apathetic.
God warned of this: "When you have eaten and are satisfied, be careful that you do not forget the Lord your God" (Deuteronomy 8:10-11). When we fast, we have the opportunity to understand the meaning behind the words, "Man does not live by bread alone but on every word that comes from the mouth of the Lord" (Deuteronomy 8:3, Matthew 4:4).
When we actually fast, we move from a concept to an experience. On the other hand, fasting should not be used to attempt to force God's hand. It should not be used as a substitute for repentance and godly living.
It certainly should not be used to impress others; that was the Pharisees' mistake (Luke 18:11-12). A right act may be robbed of all its value in the sight of God if it is done with a wrong motive. God reminds us that an acceptable fast is the one that He has chosen (Isaiah 58). Fasting, like prayer, must be God-initiated and God-ordained if it is to be effective.
Of course, we have a responsibility, too. On our part, there must be a recognition of the rightness and need for fasting, the willingness for the self-discipline involved, and the exercise of the heart before God; but in the final analysis, the initiative is His.