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.
When Christ Himself spoke to Paul and called him, He could have opened his eyes at once and made known to him the way of perfection; instead He sent him to Ananias and told him to learn from him the way of truth, saying: 'Arise and go into the city, and there you will be told what you must do' (Acts 9:6). In this manner He teaches us to be guided by those who are advanced on the way, so that the vision rightly given to Paul should not be wrongly interpreted; otherwise it might lead later generations presumptuously to suppose that each individual must be initiated into truth directly by God, as Paul was, and not by the fathers.
The fear of the Lord is the beginning of our salvation, and its constant guardian. This it is which secures both the beginning of conversion, and the purging away of vices, and the safe retention of virtues...
For this world is opposed to the world above, and this present age to the eternity above. The Christian therefore, according to Holy Scripture, must deny the world, and be translated and pass in mind out of this present age, in which the mind is placed and exposed to allurements ever since the transgression of Adam, into another age, and in frame of thought must live in the world of the Godhead above, as it is said, But our conversation is in heaven. (Phil. iii. 20.).
It is, indeed, impossible for the mind not to be troubled by thoughts, but accepting them or rejecting them is possible for everyone who makes an effort...therefore we practice the frequent reading of Scripture, so that we may be open to a spiritual point of view. For this reason we frequently chant the psalms, so that we may continually grow in compunction. For this reason we are diligent in vigils, fasting, and praying, so that the mind which has been stretched to its limits may not taste earthly things but contemplate heavenly ones. When these things cease because negligence has crept in again, then, it is inevitable that the mind, by the accumulated filth of the vices, will soon turn in a carnal direction and fall.
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.