Habit forms from custom, and habit seems to accustom itself to nature. It is much worse and more difficult to change nature. However, with God it is possible. For nature does not set itself against God.
Fasting was ordained in Paradise. The first injunction was delivered to Adam, ‘Of the tree of the knowledge of good and evil you shall not eat.’ ‘You shall not eat’ is a law of fasting and abstinence. The general argument is rather against excess than in support of ceremonial abstinence. In Paradise there was no wine, no butchery of beasts, no eating of flesh. Wine came in after the flood. Noah became drunk because wine was new to him. So fasting is older than drunkenness. Esau was defiled, and made his brother’s slave, for the sake of a single meal. It was fasting and prayer which gave Samuel to Hannah. Fasting brought forth Samson. Fasting begets prophets, strengthens strong men. Fasting makes lawgivers wise, is the soul’s safeguard, the body’s trusty comrade, the armor of the champion, the training of the athlete.
You write that after Communion you felt well. Glory be to God, Who comforts our unworthiness. And as regards the fact that this soon passed, here also is seen His fatherly providence for us. For continual consolation enfeebles the soul and makes it slothful, or leads to even greater harm. That is why the Lord takes it away quickly and again makes us feel our weakness, our helplessness, and our sinfulness. We must humble ourselves more, reproach ourselves, offer repentance for our sins, and not desire consolations, but patiently endure what God allows. Dryness and cooling of fervor are also permitted on account of vainglory.
Of the teachings and proclamations preserved in the Church, some we possess from written teaching, while others we have received in secret from the Tradition of the Apostles; these both have the same validity [ie. authority] for true religion. And no one will deny these points, at least if he is even moderately experienced in Church [matters].
No virtue makes flesh-bound man so like a spiritual angel as does self-restraint, for it enables those still living on earth to become, as the Apostle says, 'citizens of heaven' (cf. Phil. 3:20).
Through the Holy Spirit comes our restoration to paradise, our ascension into the kingdom of heaven, our return to the adoption of sons, our liberty to call God our Father, our being made partakers of the grace of Christ, our being called children of light, our sharing in eternal glory, and, in a word, our being brought into a state of all 'fullness of blessing,' both in this world and in the world to come, of all the good gifts that are in store for us, by promise hereof, through faith, beholding the reflection of their grace as though they were already present, we await the full enjoyment.
The Christian ought not to be of doubtful mind, nor by anything drawn away from the recollection of God and of His purposes and judgments. The Christian ought in all things to become superior to the righteousness existing under the law, and neither swear nor lie. The Christian ought to be patient, whatever he has to suffer, and to convict the wrong-doer in season, not with the desire of his own vindication, but of his brother's reformation, according to the commandment of the Lord.
Of the Only Case in Which Anger is Good... But we have a use for anger most properly planted within us, and for this use alone it is profitable and healthful for us to entertain it, namely, when we burn with wrathful indignation against the lustful motions of our own hearts, and are enraged to find that those things which we should be ashamed to do or to speak of before men have found admittance into the secret places of our minds. We may then well dread and fear exceedingly the presence of the Angels and the Omnipresence of God Himself, and His all-seeing Eye from which no secrets of our hearts can lie hid.
Keeping the thought of God always present before you, this form of words for your devotions is ever to be put first: O God, make speed to save me; O Lord, make haste to help me. For this verse has, not undeservedly, been taken out of the whole of scripture for this purpose. It contains all the feelings that can come upon human nature; it is very rightly and properly suited for every situation and for every need that may come upon us. Indeed it contains a calling upon God against every danger, it has the humility of a good confession, the watchfulness of constant care and fear of God, it realizes the frailty of him who prays, exhibits confidence in an answer to the prayer, and trust in the Divine protection present and ever at hand. For he who ceases not to call upon his Protector is sure of His perpetual presence.
Peace is the beginning of the purification of the soul, the tongue freed from speaking of the things of men, the eyes no longer dwelling on the beauty of bodies and elegance of our surroundings, the hearing not undoing the strength of the soul through listening to melodies that were composed for pleasure, nor through the talk of clever and frivolous men, which more than anything else has power to undo the purpose of the soul. For the mind, when not wasted on outward things, or led astray by the world of the senses, turns itself on itself, and through this ascends to the thought of God, and lit by that inward beauty becomes unmindful even of nature, and no more troubled by anxiety for its food, or with concern for clothing; at rest from earth’s cares, all its zeal is given to gaining the things that are good forever.
The full and complete definition of repentance is that we never again allow in ourselves the sins of which we repent, or whereby our conscience is stung. The mark of satisfaction and forgiveness is when we have driven out from our hearts all desire for them.
I shall speak first about control of the stomach, the opposite to gluttony, and about how to fast and what and how much to eat. I shall say nothing on my own account, but only what I have received from the Holy Fathers. They have not given us only a single rule for fasting or a single standard and measure for eating, because not everyone has the same strength; age, illness or delicacy of body create differences. But they have given us all a single goal: to avoid over-eating and the filling of our bellies... A clear rule for self-control handed down by the Fathers is this: stop eating while still hungry and do not continue until you are satisfied.
We should indeed be the strangest people if we were to find any pleasure in the schisms and divisions that beset the Church, and if we did not consider it as the greatest achievement to see the scattered limbs of Christ reassembled once more. Our desire to achieve this is as strong as the knowledge of our weakness to do so.