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.
It is impossible for the soul to be liberated from turbulent thoughts without the virtue of non-possessiveness. And without peace of the bodily senses it is impossible for the soul to have a peaceful intellect. And if it does not come into temptations it will not acquire wisdom of the Holy Spirit. And without laborious and persistence in reading, it will not come to the discernment of thoughts. And without the stillness of thoughts, the intellect cannot move to seek the hidden mysteries of God.
Just as we must beware of overeating, so too we must beware of excessive temperance or abstinence. Excessive temperance weakens the body, destroys wakefulness, coolness and freshness which are indispensable for vigilance, and which fade and weaken when the physical powers succumb and fail. If you force a weak body to labor beyond its powers, you subject your soul to double darkness, and lead it into confusion (and not relief)...
Trial is profitable for every man... Ascetic strugglers are tried, that they may add to their riches; the slothful are tried, that they may thereby guard themselves from what is harmful to them; the sleepy are tried, that they may be armed with wakefulness; those who are far away are tried, that they may draw nearer to God; those who are God's own are tried, that with boldness they may enter into His house. The son who is not trained will receive no profit from the riches of his father's house. For this reason, then, God first tries and afflicts, and thereafter reveals His gift. Glory be to our Master Jesus Christ Who brings us the sweetness of health by stringent medicines!
Let us have recourse to humility on all occasions; for the humble lie prone on the ground, and how can a man fall if he lies on the ground? But a man who stands on a height can easily fall.
The abstinent withdraws from gluttony, the uncovetous from covetousness, the silent from wordiness, the pure from attachment to sensory pleasures, the chaste from fornication, he who is content with what he has from love of money, the meek from agitation (anger), the humble from vanity, the obedient from objection, he who is honest with himself from hypocrisy; equally, he who prays withdraws from despair, the willing pauper from acquisitiveness, he who professes his faith from denying it, the martyr from idolatry – so you see that each virtue, performed even unto death, is nothing but withdrawal from sin; and withdrawal from sin is a natural action, not an action which could be rewarded by the kingdom.
Those who have sinned must not despair. Let that never be. For we are condemned not for the multitude of evils, but because we do not want to repent...
The man who is conscious of his sins is greater than he who profits the whole world by the sight of his countenance. The man who sighs over his soul for but one hour is greater than he who raises the dead by his prayer while dwelling amid many men.
As a man whose head is under water cannot inhale pure air, so a man whose thoughts are plunged into the cares of this world cannot absorb the sensations of that new world.
Ever let mercy outweigh all else in you. Let our compassion be a mirror where we may see in ourselves that likeness and that true image which belong to the Divine nature and Divine essence. A heart hard and unmerciful will never be pure.
Bring before your eyes the blessings, whether physical or spiritual, conferred on you from the beginning of your life down to the present, and call them repeatedly to mind in accordance with the words: 'Forget not all His benefits' (Ps. 102:2). Then your heart will readily be moved to the fear and love of God, so that you repay Him, as far as you can. by your strict life, virtuous conduct, devout conscience, wise speech, true faith and humility - in short, by dedicating your whole self to God. When you are moved by the recollection of all these blessings which you have received through God's loving goodness, your heart will be spontaneously wounded with longing and love through this recollection or, rather, with the help of divine grace.