When it is painful to remember the past, it is better to simply repent of what had been bad, and think no more about it. In order not to despair or be enfeebled by it, 'remember the examples of God's great mercies to great sinners. The main thing: do not condemn, do not envy, know yourself and be with God.'
There is one method which, if practiced with full attention, will seldom allow anything passionate to slip unnoticed into the heart. This is to examine our thoughts and feelings, so as to discover which they tend: towards pleasing God or towards pleasing ourselves.
Repentance is real when afterwards you keep trying strenuously to live now as you ought; but without this it is not very effectual, if you repent just to say your sins & to keep on living as before.
Remember, O my soul, the terrible and frightful wonder: that your Creator for your sake became Man, and deigned to suffer for the sake of your salvation. His angels tremble, the Cherubim are terrified, the Seraphim are in fear, and all the heavenly powers ceaselessly give praise; and you, unfortunate soul, remain in laziness. At least from this time forth arise and do not put off, my beloved soul, holy repentence, contrition of heart and penance for your sins.
He Who before our offence forbids us to sin, after our offence ceases not from waiting for us to repent, He Whom we have rejected calls after us. We have turned away from Him, but He has not turned away from us.
A man who falls into sin is different from the way he was created. He is different, because he changes by his own actions the way he was meant to be. Man renounces himself when he becomes a different person through repentance. He leaves a corrupted man, which he had become through sin, and becomes such as he once was created, through mercy.
What does spoil repentance is being again entangled in the same evils. 'For there is one' we read, 'who builds, and one who pulls down, what have they gained more than toil? He who is dipped in water because of contact with a dead body, and then touches it again, what has he gained by his washing?' Even so if a man fasts because of his sins, and goes his way again, and does the same things, who will hear his prayer? And again we read 'if a man goes back from righteousness to sin the Lord will prepare him for the sword,' and, 'as a dog when he has returned to his vomit, and become odious, so is a fool who by his wickedness has returned to his sin.'
True repentance consists of withdrawing from sin and nurturing hatred for it. For, lo, when someone says from his heart: I have hated deceit and been repelled by it - then God accepts him with joy.
Sorrow over your sins makes you as gentle and meek as a lamb; and where there is meekness and gentleness, there is serenity and beatitude. What is more precious and blessed than spiritual calm?
Let each one consider within himself what faults he must remedy in himself, what good work he may yet do, what sin he may wipe out from his soul, so that by this he may become better. And if he finds that he has made progress in this excellent market, through fasting, and is aware that there is need for much care for his wounds, then let him draw near. If however he remains neglectful of himself, and has only his fasting to show, and makes no progress in other directions, then let him remain outside, and let him return only when all his sins are cleansed.
Painstaking repentance, mourning cleansed of all impurity, and holy humility in beginners, are as different and distinct from each other as yeast and flour from bread. By open repentance the soul is broken and refined; it is brought to a certain unity, I will even say a commingling with God, by means of the water of genuine mourning. Then, kindled by the fire of the Lord, blessed humility becomes bread and is made firm without the leaven of pride. Therefore, when this holy three-fold cord or, rather, heavenly rainbow, unites into one power and activity, it acquires its own effects and properties. And whatever you name as an indication of one of them, is a token also of another. The first and paramount property of this excellent and admirable trinity is the acceptance of indignity with the greatest pleasure, when the soul receives it with outstretched hands and welcomes it as something that relieves and cauterizes diseases of the soul and great sins. The second property is the loss of all bad temper, and humility as its subsiding. The third and highest degree is a true distrust of one’s good qualities and a constant desire to learn.
It is always possible to make a new start by means of repentance. 'You fell,' it is written, 'now arise'(cf. Prov. 24:16). And if you fall again, then rise again, without despairing at all of your salvation, no matter what happens. So long as you do not surrender yourself willingly to the enemy, your patient endurance, combined with self-reproach, will suffice for your salvation. 'For at one time we ourselves went astray in our folly and disobedience,' says St. Paul. '... Yet He saved us, not because of any good things we had done, but in His mercy' (Tit. 3:3,5).
One day, a young monk came to see an elder and asked him, 'What must I do, Father? I fall continuously in the same sin.' The elder replied, 'If you fall into sin, get up and do penance.' Monk: 'And if I fall again?' Elder: 'Then get up and repent of your sin again.' Monk: 'But until when?' Elder: 'Until your death.'
Woe is he who knowingly chooses to sin with the intention to repent when morning comes, for he knows not what the coming day or the night that precedes it will bring.