In Matthew 6:1-18 Jesus contrast how the hypocrites practice three acts of piety with the way His disciples should practice them. I can imagine someone reading this section and being really convicted by the first two. They may think, “I sometimes give hypocritically, and often pray hypocritically, but I never fast hypocritically.” But they never set themselves up for the fall. They never fast hypocritically because they never fast. We’re not even sinning in the right direction.
I think we never or rarely fast hypocritically for the praise of men because there are better ways to achieve our sinful desires. In America we value appearance too much to disfigure our faces and put ashes on our heads. Why fast when there are sexier ways to look spiritual? Besides, you might be though odd for God if you were known to fast regularly. Instead of abusing God’s ordained means for our won glory, we craft our own means so that we get double the glory. We don’t need fasting, we use programs, positions, and ministries as outlets for our hypocrisy. These means, more than fasting, will lead to people seeing me, thinking me spiritual, gifted, and wise.
Our craving is for our own glory, not His. We do not fast because we are fat on the world.
Half of Christian fasting is that our physical appetite is lost because our homesickness for God is so intense. The other half is that our homesickness for God is threatened because our physical appetites are so intense. In the first half, appetite is lost. In the second half, appetite is resisted. In the first, we yield to the higher hunger that is. In the second, we fight for the higher hunger that isn’t. Christian fasting is not only the spontaneous effect of a superior satisfaction in God; it is also a chosen weapon against every force in the world that would take that satisfaction away.
The greatest enemy of hunger for God is not poison but apple pie. It is not the banquet of the wicked that dulls our appetite for heaven, but endless nibbling at the table of the world. It is not the X-rated video, but the prime-time dribble of triviality we drink in every night. For all the ill that Satan can do, when God describes what keeps us from the banquet table of his love, it is a piece of land, a yoke of oxen, and a wife (Luke 14:18-20). The greatest adversary of love to God is not his enemies but his gifts. And the most deadly appetites are not for the poison of evil, but for the simple pleasures of earth. For when these replace an appetite for God himself, the idolatry is scarcely recognizable, and almost incurable. – John Piper in A Hunger for God
No Other Boast 