Seest thou how He now proceeds to lay beforehand in them the foundation of His doctrine about fasting? ... See, at any rate, how many blessings spring from them both. For he that is praying as he ought, and fasting, hath not many wants, and he that hath not many wants, cannot be covetous; ...
-St. John Chrysostom, Homily 57 on Matthew 17,4,5. B#54, pp.355,356., 4th Century


... he that is not covetous, will be also more disposed for almsgiving. He that fasts is light, and winged, and prays with wakefulness, and quenches his wicked lusts, and propitiates God, and humbles his soul when lifted up. Therefore even the apostles were almost always fasting.
-St. John Chrysostom, Homily 57 on Matthew 17,4,5. B#54, pp.355,356., 4th Century


He that prays with fasting hath his wings double, and lighter than the very winds. ... For nothing is mightier than a man who prays sincerely. ... But if thy body be too weak to fast continually, still it is not too weak for prayer, nor without vigor for contempt of the belly. For although thou canst not fast, yet canst thou avoid luxurious living.
-St. John Chrysostom, Homily 57 on Matthew 17,4,5. B#54, pp.355,356., 4th Century