Another bit from the monasticism chapter of the forthcoming Medieval Wisdom: An Exploration with C S Lewis:
The concept of askesis came from the pagan philosophers, but it is thoroughly supported in Scripture. It is like the discipline of an athlete who, in the words of the Apostle Paul, must “beat his body”—endure some pain and deprivation—if he is to use that body to excel. Following from the phrase in the title of this post: I Cor 9:26-27 “Everyone who competes in the games goes into strict training. They do it to get a crown that will not last, but we do it to get a crown that will last forever.” Therefore I do not run like a man running aimlessly; I do not fight like a man beating the air. No, I beat my body and make it my slave so that after I have preached to others, I myself will not be disqualified for the prize.”
If we are to excel spiritually, the church has always known, we must practice certain disciplines that keep our physical, emotional, and intellectual lives in check; some of these disciplines actually involve denying ourselves some of the good, God-given pleasures we might otherwise enjoy in those realms. Christians through the centuries have practiced such self-denial not as an end in itself, but in the interest of that higher goal of union with God.