Ascesis and its derivative—asceticism—come from the Greek verb askeō, which means to exercise. Whether the term originated with Christianity is debatable, but certainly the Middle Platonists and the Stoics had specific ascetic practices associated with their respective philosophical schools and according to Pierre Hadot in Philosophy as A Way of Life ascetic practices were part and parcel of every ancient school of philosophy.
Unfortunately, within our context, asceticism has come to be identified exclusively with monasticism. In many ways, (western) monasticism developed from the ascetic background of the Christian faith which is already evident in St. Paul (cf. 1 Cor. 9:24-27) and while Christian monasticism can be seen as perhaps the pinnacle of Christian asceticism, it would take away from the Christian tradition as a whole to see ascesis as something that is only expected or appropriate for monastics.
Most believers are familiar with many of the most common Christian ascetic practices: fasting, prayer, penance, and study of the Scriptures. Sometimes, however, these tasks are undertaken as if they were simply additions to a to-do list, as if completing them were their principal aim. In the passage from 1 Corinthians above, Paul highlights the connection between ascesis—which is to say spiritual exercise—and regular physical exercise. A runner is not primarily concerned with transporting himself or herself from point A to point B, neither is a lifter primarily concerned with lifting a particular weight so many times.
The most important part of either of those two exercises is not merely completing them, but completing them in the right way and producing the right effect. Thus, the lifter who lifts the weight with bad form accomplishes having lifted that weight say 30 times, but not only does that work not serve to exercise the intended muscle group, but it may even cause significant damage. The runner has nothing to gain from running three miles, he or she does not just need to be somewhere three miles away really fast and the lifter does not just need to put some heavy stuff in the top cabinet. The ultimate purpose of those exercises is to gain stamina, or to gain muscle mass, or to lose weight.
The same is true for spiritual exercise. The point of fasting is not to save food or to adopt a healthy diet. Fasting should produce greater self-control and discipline and free us from the concerns of the stomach so more time can be devoted to prayer. If one fasts but spends the whole day thinking about the fact that they are fasting, they are lifting, but with bad form.
Nothing is more crucial to understand in this case than prayer. In the Sermon on the Mount, Jesus says, “When you are praying, do not heap up empty phrases as the Gentiles do; for they think that they will be heard because of their many words. Do not be like them, for your Father knows what you need before you ask Him” (Mt. 6:7-8). In commenting on these verses, Augustine says that “all superfluity of discourse has come from the Gentiles, who labor rather to practice their tongues than to cleanse their hearts, and introduce this art of rhetoric into that wherein they need to persuade God” (Ep. 130, 10). Prayers are not merely speeches addressed to God. The Lord tells us God already knows what we need, before we ask Him. Prayer, then, performs several functions. First, in petitioning God we recognize that we are dependent on Him. Second, we give Him right praise for His goodness and all that He does for us. Third, we remind ourselves by the content of our prayer of Who God is and what He has done for us.
The governing principle of the Roman religion was do ut des, “I give so that you may give.” The Roman method of practicing religion was nothing more than a contract between the people and the gods, where the people would give the gods sacrifices and beautiful temples and the gods would, in turn, reward them with favorable weather, good harvests, success in war, and so on and so forth. The Christian God, on the other hand, does not need us or our prayers. We have no leverage on Him. In addition, He tells us that He already knows what we need. If we are not conscious of this fact, that prayer is exercise for us, we are a bit like the hurdles runner who figures he or she can get to the finish line much quicker if they run to the side and skip the hurdles, sprinting to the finish line only to find out that all their effort was pointless. Let us also not be confused about the purpose of our tasks. We do not aim to convince God or to persuade Him, but rather to conform to His will and to exercise ourselves for the purpose of being more like Him. If we do not pursue fasting and prayer in this way, we are merely exercising in bad form.