St. Peter of Damascus teaches, 'When joy comes, represent sorrow to yourself; and when you are encompassed by sorrow, try to awaken joy.' Thus you will be safeguarded both against deception and against despair.
It is impossible for the mind to escape disturbing thoughts, but it is possible, for any who take sufficient care, either to admit them or reject them.
Train yourself to cut off an intrusive thought immediately… Be at pains over this, so that you acquire the habit. The soul is a creature of habit: according to the habit you have acquired, so will you act all the rest of your life.
After a spiritual conversation with Brother A. concerning what is profitable for the soul, I afterwards realized the absolute necessity of remembering never to begin speaking to my brother concerning what is profitable for the soul or concerning correction, and also not to listen to another’s explanations without first mentally turning to the Lord and asking His enlightenment for me and for my brother, and then speaking with awareness of God’s presence. And after the conversation both people must again turn to Christ the Savior and pray for His aid in fulfilling the Gospel and His all-good will as we were able to discern it in our conversation together. Let not our consultation together be in idleness, but remembering the words of our Lord Jesus Christ, ‘If two of you shall agree as touching any thing and ask My Father in My Name, He shall give it to you’ (cf. Matthew 18:19), let us have undoubting hope for our correction in all things.
We must always pray to the Lord to tell us what to do, and the Lord will not let us go astray. Adam was not wise enough to ask the Lord about the fruit which Eve gave him, and so he lost paradise.
If we desire to acquire faith the foundation of all blessings, the door to God's mysteries, unflagging defeat of our enemies, the most necessary of all the virtues, the wings of prayer and the dwelling of God within the soul--we must endure every trial imposed by our enemies and by our many and various thoughts... if we forcibly triumph over the trials and temptations that befall us, it will not be we who are victorious, but Christ, Who is present in us through faith.
For by prayer we obtain the divine favor, by fasting we extinguish the concupiscences of the flesh, by almsgiving sins are redeemed (Dan. iv. 24); and by all three together, the image of God is renewed in us, provided that we are ever ready in His praise, eager without ceasing for our own purification, and disposed at all times to assist our neighbor.
Restrain the excitable power of your soul by love; mortify the desiring power by self-mastery; give wings to the thinking power by prayer, and the light of your mind will never be dimmed.
From this minute of his new life, the repentant sinner commences his podvig, struggle, and labor, and begins to bear the burden, the yoke. This is so essential that all the saints accept the only true path to virtue to be pain and hard work. On the contrary, lightness and ease are a sign of a false path, for the kingdom of God suffereth violence, and the violent take it by force (Matt. 11:12). Anyone who is not struggling, not in podvig, is in prelest.
Be slow and dull to idle talk, but knowing and wise in hearkening to the saving words of the Holy Scriptures. Let the hearing of worldly tales be to you as a bitter taste in your mouth, but the discourse of holy men as a honeycomb (Prov. 16.24). Be eager to imitate men of disciplined habits and do not wait to be taught each thing. Strive to attain to the greater virtues, but do not neglect the lesser ones. Do not make light of a fall even if it be the most venial of faults; rather, be quick to repair it by repentance, although many others may commit a large number of faults, slight and grievous, and remain unrepentant. Judge not the sins of others, for they have a just Judge ‘Who will render every man according to his works’ (Rom. 2.6); but be master of what is your own and lighten your own burden insofar as you have the power, for he who increases his own burden will also carry it. In repentance is salvation, but folly is the death of repentance.
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.
The most important thing during illness is to offer to God patience and thanksgiving for His merciful visitations. Sickness purifies sins and gives one time to meditate on the past.