One should not ponder divine matters on a full stomach, say the ascetics. For the well-fed, even the most superficial secrets of the Trinity lie hidden.
To act 'according to one’s strength' means to use a little less than necessary both of food, and drink, and sleep... As for food, restrain yourself when you wish to eat a little more, and in this way you will always make use of it moderately.
When you intend to do something and see that your thought is perturbed, and if after invoking God's Name it remains perturbed even by a hair's breadth, know from this that the action you mean to commit is from the evil one and refrain from commiting it. For nothing done with perturbation is pleasing to God.
Watch constantly, learning to understand God's law, for this warms the heart with heavenly fire. Guard your lips from the idle word, or empty talk, lest the heart gets used to evil words.
You have no peace from thoughts, which impel you to trouble others, and in turn to be troubled by others. But know, my brother, that if we offend by word or deed, we are thereby ourselves offended a hundredfold. Be longsuffering in all things and refrain from letting your own will enter into anything. Carefully examine your thoughts lest they infect your heart with deadly poison (ill temper) and make you take a gnat for a camel, a pebble for a cliff, and lest you become like a man who has a beam in his own eye but beholds the mote in the eye of another.
If you wish to be delivered from shameful passions, do not behave with anyone familiarly, especially with those toward whom your heart is inclined by a lustful passion; through this you will be delivered also from vainglory. For in vainglory is involved the pleasing of men, in the pleasing of men is involved familiarity of behavior, and familiarity of behavior is the mother of all passions.
When anyone is disturbed or saddened under the pretext of a good and soul-profiting matter, and is angered against his neighbor, it is evident that this is not according to God: for everything that is of God is peaceful and useful and leads a man to humility and to judging himself.
One must train oneself in self-reproach, that is, always accuse oneself & not others in one’s mind, reproach oneself and not others, and with a severe distrust of oneself accuse oneself of the failings which are covered up by our self-love, accuse ourself of our inclinations to sin. He who has self-reproach has peace, writes Abba Dorotheos, & will never be disturbed. If to such a one there should occur an illness, a wrong, a vexation, or some similar misfortune, he ascribes everything to his own sins & thanks God. If such a one is punished or reprimanded by the superior, he accepts all this as good & accepts every severe word against himself without murmuring or talking back, as the judgment of God.
Though you pray to God every hour, though you have such faith that you can move mountains, even though you give away all of your belongings to the needy, and give your body to be burned, - if you do not practice forgiveness and do not wish to forgive your enemy, then all is in vain, for in such circumstances neither prayer, nor faith, nor charity, will save you, in short, nothing will save you.
What is self-justification? - Self-justification is when a man denies his sin, as we see in the case of Adam, Eve, Cain and others who have sinned but, wishing to justify themselves, denied their sin.
Concerning fasting, do not grieve, as I have said to you before: God does not demand of anyone labors beyond his strength. And indeed, what is fasting if not a punishment of the body in order to humble a healthy body and make it infirm for passions, according to the word of the Apostle: 'When I am weak, then am I strong' (II Corinthians 12:10).
No, the God of love and peace and complete sacrifice does not care to live in the midst of bustling and ado to please oneself, even if this is carried on perhaps under some kind of pretence. There is one way to make a test: if your peace of mind is troubled, if you become dejected or perhaps a little angry if for some reason you have to give up performing the good deed you had planned, then you know that the spring was muddy.
Often when someone throws a rock at a dog, rather than rushing at the person who threw the stone, the dog will run and bite the stone. We do the same thing. The tempter uses someone else to tempt us, either in word or deed, and, rather than deal with the tempter who threw the stone, we bite the rock, our fellow man that the hater of the good used against us.
True joy is the joy of consolation, the joy that wells up in the knowledge of one's own weakness and the Lord's mercy, and that does not need the bared teeth of laughter to express itself.
Give thanks to God for all things, because thanksgiving is intercession before God for our weakness. Judge yourself always and in everything as a sinner and as one seduced - and so God will not judge you; be humble in everything and you will receive grace.