A prayer offered while one has any cause to reproach a fellow man is an impure prayer. There is only one whom the praying person may and must reproach, and that is himself. Without self-reproach, your prayer is as worthless as it is while you are reproaching someone else in your heart. Perhaps you ask: How can one learn this? The answer is: One learns it through prayer.
No, the God of love and peace and complete sacrifice does not care to live in the midst of bustling and ado to please oneself, even if this is carried on perhaps under some kind of pretence. There is one way to make a test: if your peace of mind is troubled, if you become dejected or perhaps a little angry if for some reason you have to give up performing the good deed you had planned, then you know that the spring was muddy.
It took Noah a hundred years to build his ark; log upon log he dragged to the construction. Do as he did; drag log upon log to your construction, patiently, in silence, day after day, and do not inquire about your surroundings. Remember that Noah was the only on in the whole world who 'walked with God' (Gen. 6:9), that is, in prayer. Imagine the crowding, the darkness, the stench, that he had to live in until he could step out into the pure air and build an altar to the Lord. The air and the altar you will find within you, explains St. John Chrysostom, but only after you have willingly gone through the same narrow gate as Noah.
Think also of this: the person who is bound to earthly things may rejoice but may also be upset or disturbed or grieved over earthly things: his mind is exposed to continual changes. But the joy of your master (Matthew 25:21) is enduring, for God is unchangeable. Thus control your tongue at the same time as you discipline your body with fasting and strictness. Talkativeness is a great enemy of prayer. A spate of fluttering words stands in the way of the words of prayer. This is the reason that we shall render account for every careless word we utter (Matthew 12:36). One does not bring the dust of the road into a room that one wishes to keep clean; thus keep your heart free from gossip and chatter about the events of the day that is past.
But, say the saints, now that you recognize the darkness in your own heart and the weakness of your flesh, you lose all desire to pass judgment on your neighbor. Out of your own darkness you see the heavenly light that shines in all created things reflected the clearer: you cannot detect the sins of others while your own are so great. For it is in your eager striving for perfection that you first perceive your own imperfection. And only when you have seen your imperfection, can you be perfected. Thus perfection proceeds out of weakness.
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 honor your patience.
The holy Fathers' counsel is to begin with small things, for, says Ephraim the Syrian, how can you put out a great fire before you have learned to quench a small one? If you wish to set yourself free from a great suffering, crush the small desires, say the holy Fathers. Do not suppose that the one can be separated from the others: they all hang together like a long chain or a net.
When we stand in prayer, those unclean and unspeakable thoughts (blasphemy) assail us; but if we continue praying to the end, they retire at once, for they do not fight those who stand up to them.
You must set about rooting out the very desire to have things pleasant, to get on well, to be contented. You must learn to like sadness, poverty, pain, hardship. You must learn to follow privately the Lord's bidding: not to speak empty words, not to adorn yourself, always to obey authority, not to look at a woman with desire, not to be angry and much else. For all these biddings are given us not in order for us to act as if they did not exist, but for us to follow: otherwise the Lord of mercy would not have burdened us with them. If any man will come after me, let him deny himself, He said (Matthew 16:24), thereby leaving it to each person's own will ... and to each person's endeavor: let him deny himself.
Spiritual activity embodies Christ in our soul. This involves continual remembrance of the Lord: you hide Him within, in your soul, your heart, your consciousness.