The full and complete definition of repentance is that we never again allow in ourselves the sins of which we repent, or whereby our conscience is stung. The mark of satisfaction and forgiveness is when we have driven out from our hearts all desire for them.
I shall speak first about control of the stomach, the opposite to gluttony, and about how to fast and what and how much to eat. I shall say nothing on my own account, but only what I have received from the Holy Fathers. They have not given us only a single rule for fasting or a single standard and measure for eating, because not everyone has the same strength; age, illness or delicacy of body create differences. But they have given us all a single goal: to avoid over-eating and the filling of our bellies... A clear rule for self-control handed down by the Fathers is this: stop eating while still hungry and do not continue until you are satisfied.
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.
You describe how bitterly you regret the inefficacy of your prayers. Beware: to wish for consolation or revelation in prayer is a sure sign of pride. Pray humbly, in perfect simplicity, seeking salvation only through forgiveness, & having faith that God will extend to you His mercy - as He did to the publican.
Pray simply. Do not expect to find in your heart any remarkable gift of prayer. Consider yourself unworthy of it. Then you will find peace. Use the empty cold dryness of your prayer as food for your humility. Repeat constantly: I am not worthy; Lord, I am not worthy! But say it calmly; without agitation.
The grace of the Spirit is one and unchanging, but energizes in each one of us as He wills. When rain falls upon the earth, it gives life to the quality inherent in each plant: sweetness in the sweet, astringency in the astringent; similarly, when grace falls upon the hearts of the faithful, it gives to each the energies appropriate to the different virtues without itself changing.
Keep your mind from malicious thoughts of your neighbors, knowing that such thoughts are hurled by diabolical power, to keep your mind from your own sins and from seeking.
The enemy constantly endeavors to awaken in the abyss of the human heart a great turmoil about trifles. This is one of his tricks to blind our soul to the sun of truth, Christ our Lord, hidden in the heart's core of every one of our neighbors.
Your past and present torments and sufferings are poured down upon you to test your faith and 'steel' it; they also work to curb your lusts and passions. Humble yourself. God gives help to the humble. Judgment of others, insistence on their shortcomings, can only increase the bitterness of your sorrow. Choose the better part.
The enemy is within ourselves. An invisible war is taking place within us. If interior evil is defeated, then the external, weaker, foe will surrender.
Be glad and rejoice that you were granted to be pious Orthodox Christians. Likewise again cry and mourn for the impious and unbelievers who walk in darkness, in the hands of the devil.
In order to preserve the mind and body in a perfect condition abstinence from food is not alone sufficient: unless the other virtues of the mind as well are joined to it. And so humility must first be learned by the virtue of obedience, and grinding toil and bodily exhaustion. The madness of anger should be controlled; the downcast look of dejection be overcome; vainglory should be despised, the disdainfulness of pride trampled under foot, and the shifting and wandering thoughts of the mind restrained by continual recollection of God. And the slippery wanderings of our heart should be brought back again to the contemplation of God as often as our crafty enemy, in his endeavour to lead away the mind a captive from this consideration, creeps into the innermost recesses of the heart.
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.
When you see someone suffering great dishonor, you may be sure that he was carried away by thoughts of self-esteem and is now reaping, much to his disgust, the harvest from the seeds which he sowed in his heart.
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.