He who knows himself pays no heed to the sins of others, but looks at his own and is always repenting over them; he reflects concerning himself, and condemns himself, and does not interfere in anything apart from his own position.
Even a pious person is not immune to spiritual sickness if he does not have a wise guide -- either a living person or a spiritual writer. This sickness is called prelest, or spiritual delusion, imagining oneself to be near to God and to the realm of the divine and supernatural. Even zealous ascetics in monasteries are sometimes subject to this delusion, but of course, laymen who are zealous in external struggles (podvigi) undergo it much more frequently. Surpassing their acquaintances in struggles of prayer and fasting, they imagine that they are seers of divine visions, or at least of dreams inspired by grace. In every event of their lives, they see special intentional directions from God or their guardian angel. And then they start imagining that they are God's elect, and often try to foretell the future. The Holy Fathers armed themselves against nothing so fiercely as against this sickness -- prelest.
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!
God the Word, the God-Man, our Lord Jesus Christ, compares our life with a market, and the work of our life on earth He calls trading, and says to us all: Trade till I come (Luke 19:13), redeeming the time, because the days are evil (Ephesians 5:16). That is to say, make the most of your time for getting heavenly blessings through earthly goods. Earthly goods are good works done for Christ's sake and conferring on us the grace of the All-Holy Spirit.
It is just as shameful for lovers of the flesh and the belly to search out spiritual things as it is for a harlot to discourse on chastity. A body suffering grave illness shuns fatty foods and abhors them; and likewise, a mind occupied with worldly affairs cannot approach the inquiry into things of God. A fire cannot be ignited with wet wood, nor can the divine fervor be kindled in a heart that loves ease.
Love of God proceeds from conversing with him; this conversation of prayer comes about through stillness, and stillness comes with the stripping away of the self.
We must with unflagging zeal and care give ourselves to the pursuit of virtue, and constantly occupy ourselves in its practice, lest at any time progress may cease, and regress immediately take its place.... To cease to acquire means to lose, for the will which goes no longer forward will not be far from peril of falling back.
The belly when filled with all kinds of food gives birth to seeds of wantonness, nor can the mind, when choked with the weight of food, keep the guidance and government of the thoughts. For not only is drunkenness with wine wont to intoxicate the mind, but excess of all kinds of food makes it weak and uncertain, and robs it of all its power of pure and clear contemplation. The cause of the overthrow and wantonness of Sodom was not drunkenness through wine, but fullness of bread. Hear the Lord rebuking Jerusalem through the prophet. 'For how did thy sister Sodom sin, except in that she ate her bread in fullness and abundance?' (Ezek. xvi. 49)
'Grace always precedes temptations.' He knew that grace always precedes temptations as a forewarning preparation. As soon as you perceive grace, gird yourself and say: 'Here comes the call to battle! Beware, attend, O Clay, to where the wicked on will strike the battle. Many times it comes quickly, and many times after two or three days. In any event, it will come, and the earthworks must be firm. Confessions every evening, Obedience to the elder, humility and love towards all. By these means lighten the affliction.' Grace is divided into three stages: purifying, enlightening, and perfecting. So also are deeds: natural, supernatural, contranatural. According to these three stages on ascends and descends. The great gifts one receives are also three: contemplation, love, dispassion.'
A righteous person who is wise resembles God: he never disciplines anyone in order to take vengeance upon a wrongdoing, but only so that the person may be set aright, or that others may be deterred.
As a man cannot remain unscathed who spares his enemy on the field of battle, so a man engaged in spiritual warfare cannot save his soul if he spares his body.