I should wonder at the Psychics, if they were enthralled to voluptuousness alone, which leads them to repeated marriages, if they were not likewise bursting with gluttony, which leads them to hate fasts. Lust without voracity would certainly be considered a monstrous phenomenon; since these two are so united and concrete, that, had there been any possibility of disjoining them, the pudenda would not have been affixed to the belly itself rather than elsewhere. Look at the body: the region (of these members) is one and the same. In short, the order of the vices is proportionate to the arrangement of the members. First, the belly; and then immediately the materials of all other species of lasciviousness are laid subordinately to daintiness: through love of eating, love of impurity finds passage. I recognize, therefore, animal faith by its care of the flesh (of which it wholly consists)--as prone to manifold feeding as to manifold marrying--so that it deservedly accuses the spiritual discipline, which according to its ability opposes it, in this species of continence as well; imposing, as it does, reins upon the appetite, through taking, sometimes no meals, or late meals, or dry meals, just as upon lust, through allowing but one marriage.

There is an appetite for God. And it can be awakened. I invite you to turn from the dulling effects of food and the dangers of idolatry, and to say with some simple fast: "This much, O God, I want you." Our appetites dictate the direction of our lives - whether it be the cravings of our stomachs, the passionate desire for possessions or power, or the longings of our spirits for God. But for the Christian, the hunger for anything besides God can be an arch-enemy. While our hunger for God - and Him alone - is the only thing that will bring victory. Do you have that hunger for Him? As John Piper puts it: "If we don't feel strong desires for the manifestation of the glory of God, it is not because you have drunk deeply and are satisfied. It is because we have nibbled so long at the table of the world. Our soul is stuffed with small things, and there is no room for the great." If we are full of what the world offers, then perhaps a fast might express, or even increase, our soul's appetite for God. Between the dangers of self-denial and self-indulgence is this path of pleasant pain called fasting. It is the path John Piper invites you to travel in this book. For when God is the supreme hunger of your heart, He will be supreme in everything. And when you are most satisfied in Him, He will be most glorified in you.

The author praises Gratian’s zeal for instruction in the Faith, and speaks lowly of his own merits. Taught of God Himself, the Emperor stands in no need of human instruction; yet this his devoutness prepares the way to victory. The task appointed to the author is difficult: in the accomplishment whereof he will be guided not so much by reason and argument as by authority, especially that of the Nicene Council.