Every tribulation reveals the state of our will, whether it inclines to the right or to the left. An unexpected tribulation is called temptation, because it subjects a man to a test of his secret dispositions.
The old man was asked, 'What is the good of the fasts and watchings which a man imposes on himself?' and he replied, 'They make the soul humble. For it is written, Consider my affliction and my trouble, and forgive all my sins' (Psalm 25:18). 'So if the soul gives itself all this hardship, God will have mercy on it.' The old man was (also) asked, 'What should a man do in all the temptations and evil thoughts that come upon him?' The old man said to him, 'He should weep and implore the goodness of God to come to his aid, and he will obtain peace if he prays with discernment. For it is written, 'With the Lord on my side I do not fear. What can man do to me?' (Psalm 118:6).
There is a sin which is always 'unto death' [1 Jn 5:16]; the sin which we have not repented. Even a saint's prayers will not be heard for the unrepented sin. The person who repents correctly does not imagine that his sins are cancelled through his own effort; but knows that through this effort he makes peace with God.
If we want to do something but cannot, then before God, Who knows our hearts, it is as if we have done it. This is true whether the intended action is good or bad.
The old man (Abba Moses) was asked, 'What is the good of the fasts and watchings which a man imposes on himself?' and he replied, 'They make the soul humble. For it is written, ‘Consider my affliction and my trouble, and forgive all my sins’ (Psalm 25:18). So if the soul gives itself all this hardship, God will have mercy on it.'
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.
In his famous book, 'The Ladder', St John Climacus records the life of this saint. The young Acacius was a novice with an evil elder in the monastery on Sinai. The foul-tempered elder daily groused and grumbled at Acacius, and often beat him, tormenting and ill-treating him in every possible way. Acacius did not complain, but bore it all patiently and with trust that it would work for his salvation. When anyone asked him how he survived, he replied : 'Well, as before the Lord God'. After nine years of obedience and ill-treatment, Acacius died. The elder buried him and then went off to lament to another elder, a holy man, saying: 'Acacius, my disciple, is dead. 'I don't believe it' replied the holy elder , 'Acacius is not dead.' They then both went to the dead man's grave, and the holy elder called out: 'Brother Acacius, are you dead?' The obedient Acacius, obedient even in death, replied: 'I am not dead; the obedient cannot die.' Then the evil elder repented and shut himself in a cell near Acacius's grave, where he spent the rest of his life in repentance and prayer.
The Lord commands all men to repent (Matt. 4:17), so that even the spiritual and those making progress should not neglect this injunction and fail to give attention to the smallest and most subtle errors.
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.