Grace abides in us from the time of our holy baptism; but, through our inattention, vanity and the wrong life we lead it is stifled, or buried. When a man resolves to lead a righteous life and is zealous for salvation, the fruit of his whole labor is, therefore, the restoration in force of this gift of grace. It comes to pass in a two-fold manner: first, this gift becomes revealed through many labors in following the commandments; insofar as a man succeeds in following the commandments, this gift becomes more radiant and brilliant. Secondly, it manifests and reveals itself through constant invocation of the Lord Jesus in prayer. The first method is powerful, but the second is more so, so that even the first method gains power through it. Thus, if we sincerely wish to open the seed of grace concealed in us, let us hasten to train ourselves in this latter exercise of the heart, and let us have only this work of prayer in our heart, without forms, without images, till it warms our heart and makes it burn with ineffable love of the Lord.
Those who struggle, regain their original state by keeping two commandments - obedience and fasting; for all evil entered into the generation of mortals through practices opposed to them. Moreover, those who keep the commandments through obedience ascend to God more quickly, and those who keep them through fasting - more slowly. Besides, obedience is more suitable for beginners, and fasting for those on the way, who possess courage and vision of mind. But in fulfilling the commandments it is given to very few always to obey God undeceived, and even for the most valiant this achievement is very difficult.
You write that after Communion you felt well. Glory be to God, Who comforts our unworthiness. And as regards the fact that this soon passed, here also is seen His fatherly providence for us. For continual consolation enfeebles the soul and makes it slothful, or leads to even greater harm. That is why the Lord takes it away quickly and again makes us feel our weakness, our helplessness, and our sinfulness. We must humble ourselves more, reproach ourselves, offer repentance for our sins, and not desire consolations, but patiently endure what God allows. Dryness and cooling of fervor are also permitted on account of vainglory.
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.
In words of boastfulness and self-justification there always lie concealed contrariness and pride, from which God turns away. After sinning one ought immediately to 'flee.' But you say, where? To the calm haven of heartfelt repentance.
A brother who shared a lodging with other brothers asked Abba Bessarion, 'What should I do?' The old man replied, 'Keep silence and do not compare yourself with others.'
The Lord says: 'In your patience possess ye your souls' (Luke 21:19). He did not say: in your fast or in your vigil. By patience I mean that patience which is of God and is the queen of virtues and the basis of manly valor. It is in itself - peace amid strife, stillness in the midst of storm and an impregnable position for those who have acquired it.