St. Theophan the Recluse on Fasting
“Not that which goeth into the mouth defileth a man; but that which cometh out of the mouth, this defileth a man.”(Маt. 15:11)The Lord did not say this because he did not approve of fasting or because he considered fasting unnecessary – indeed, He Himself fasted, and taught His disciples to do so, and established fasts in His Holy Church. He said this, then, not to discourage fasting. Rather, he says it to teach us that when we fast we should not limit ourselves merely to eating little and avoiding cooked foods, but should also refrain from indulging the appetites and passionate inclinations of the soul. This is, of course the most important thing. Fasting, in its turn, serves a powerful means of accomplishing this.
The passions are rooted in the flesh. When the flesh is weakened through fasting, then it is as if the fortress of the passions has been undermined, and its strength crumbles. On the other hand, to overcome the passions without fasting would be as remarkable as standing in a fire without being burnt. How is it possible for one who continually indulges his flesh with food, sleep and rest to maintain any sort of attention and purpose in spiritual matters? For such a one to turn from the earth, directing his attention to invisible things and striving them, is just as difficult as it is for an enfeebled bird to rise up from the earth
