No worship—no preaching, no singing, no praying, no fasting, however intense or beautiful—that leaves us harsh with our workers on Monday, or contentious with our spouses at home, or self-indulgent in other areas of our lives, or angry enough to hit somebody, is true, God-pleasing worship. Don’t make a mistake here: true fasting may be a God-blessed means of overcoming harshness at work, and contentiousness at home, and self-indulgence and anger. But if fasting ever becomes a religious cloak for minimizing those things and letting them go on and on, then it becomes hypocrisy and offensive to God.

Monday’s Work Proves Sunday’s Worship

How you treat people on Monday is the test of the authenticity of your fasting on Sunday. Fasting that leaves our daily lives unchanged in sin is the butt of God’s ridicule: “Is it a fast like this … for bowing one’s head like a reed?” (verse 5). In other words, the gestures of such fasting are no more spiritual than a bent reed in the swamp.

Woe to the fasting that leaves sin in our lives untouched. The only authentic fasting is fasting that includes a spiritual attack against our own sin. Is our fasting really a hunger for God? We test whether it is by whether we are hungering for our own holiness. To want God is to hate sin. For God is holy, and we cannot love God and love sin. Fasting that is not aimed at starving sin while feasting on God is self-deluded. It is not really God that we hunger for in such fasting. The hunger of fasting is a hunger for God, and the test of that hunger is whether it includes a hunger for holiness.

John Piper, A Hunger for God: Desiring God through Fasting and Prayer (Wheaton, IL: Crossway Books, 1997), 135–136.

I have just completed a series of lessons on the theme of Loving God. They are available on Amazon in both print and Kindle versions, as well as part of my Good Questions Have Groups Talking Subscription service. For a medium-sized church, lesson subscriptions are only $10 per teacher per year.