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
An elder said: “Bare your sword.” The brother said: “My passions do not let me.” The elder replied: “‘Call upon me in the day of your trouble and I will deliver you and you shall glorify me’ [Ps 49:15]. Call upon Him then, and He shall deliver you from every temptation.”
The Anonymous Sayings of the Desert Fathers (p. 23). Cambridge University Press.
“The Lord knows our weaknesses and He has granted us daily repentance until we die. St. John of the Ladder writes: ‘Previous habit often tyrannizes even over him who deplores it. And no wonder! The account of the judgements of God and our falls is shrouded in darkness, and it is impossible for us to comprehend it’. He says further: ‘Do not be surprised that you fall every day; do not give up, but stand your ground courageously. And assuredly the Angel who guards you will honour your patience’. St. Abba Dorotheos says: ‘A man who drinks once is not called a drunkard, nor is a person who once commits fornication called a fornicator… but only when these are habits’. According to spiritual knowledge, even punishments differ. Lenience should be shown towards a person who strives for virtue and falls, for he was not aiming at sin, but was unexpectedly tempted. But severe punishment is needed for one who does not strive for virtue so that he may come to his senses and do so. Thus your single weakness too deserves lenience; a mere trifle. More likely a touch of pride is disturbing you. ‘How could I let this happen?’ The Lord keep you.”
From the book: Christ is in Our Midst, Letters from a Russian Monk, by Fr. John.