Upon Our Lord's Sermon on the Mount, VII

A passage from the sermon

Fasting is enjoined by our Lord; not arbitrarily, not as a thing of itself meritorious; but as a help to break the bands of our outward sins, and an instrument of finding mercy from God. The natural advantages of fasting are likewise considerable: it tends to bring the body into subjection to the soul, and to subdue those passions which the indulgence of appetite is wont to inflame.

Let him who fasts beware of two extremes: of taking too little upon him, by fasting only outwardly while his heart remains untouched; and of taking too much upon him, by overstraining nature and impairing his health. Let it be done with humility and joy, that thy Father which is in secret may reward thee openly.