The Lord calls to him all sinners; He opens His arms wide, even to the worst among them. Gladly He takes them in His arms, if only they will come to Him.” — St. Macarius of Optina
Men have fallen into unbelief because they have either completely lost the spirit of prayer, or they never had it at all, nor have it now- in short, because they do not pray. The prince of this world has full scope for action in the hearts of such men; he becomes their master. They have not asked and do not ask God’s grace in prayer (for God’s gifts are only given to those who ask and seek) and thus their hearts, corrupt by nature, become dried up without the vivifying dew of the Holy Spirit, and at last from their extreme dryness they take fire, and blaze with the infernal flame of unbelief and various passions, and the Devil only knows how to inflame the passions that keep up this terrible fire, and triumphs at the sight of the ruin of the unfortunate souls that redeemed by the blood of Him Who has trampled the power of Satan underfoot.
St. John of Kronstadt
There is a sin which is always ‘unto death’ (1Jn 5:16): the sin for which we do not,
repent. For this sin even a saint’s prayers will not be heard.
St. Mark the Ascetic; On Those Who Believe They are Made Righteous by Works, v 44, The Philokalia
If you do not want to suffer evil, do not inflict it, since the suffering of it inevitably follows its infliction. ‘For whatever a man sows he will also reap’ (Gal. 6:7).
St. Mark the Ascetic “On the Spiritual Law; 200 texts”, Philokalia Vol. 1
Once, Abba Isaiah saw someone committing a grave sin. The “starets” did not accuse
him but said to himself: “If God, Who created him, sees this and is merciful toward him, then who am I to accuse him?”
“Abba Zosimas said: “If one brings to mind someone who caused him to be upset, ridiculed him, hurt him, or has in any way caused him some evil, he should think of him as a physician and from the depths of his heart thank him for these things. …If, indeed, he truly wishes to be cured, it is to his benefit to consider the person who troubled him his benefactor and to accept all the evil things coming from that person as therapeutic medicines that have been sent to him by Jesus.” -The Evergetinos
“Someone inquired of Abba Macarios saying, ‘How should one pray?’ The elder said this: ‘There is no need to use many words, but it suffices to lift up your hands and say: ‘Lord, as Thou willst and as Thou seest, have mercy.’ And if the warfare persists: ‘Lord help!’ And He knows what is in our interest, doing unto us according to His mercy.”
Patrologia Graecae 65:269C