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.
Whether you pray with brethren or alone, try to pray not simply as a routine, but with conscious awareness of your prayer. Conscious awareness of prayer is concentration accompanied by reverence, compunction and distress of soul as it confesses its sin with inward sorrow.
The abstinent withdraws from gluttony, the uncovetous from covetousness, the silent from wordiness, the pure from attachment to sensory pleasures, the chaste from fornication, he who is content with what he has from love of money, the meek from agitation (anger), the humble from vanity, the obedient from objection, he who is honest with himself from hypocrisy; equally, he who prays withdraws from despair, the willing pauper from acquisitiveness, he who professes his faith from denying it, the martyr from idolatry – so you see that each virtue, performed even unto death, is nothing but withdrawal from sin; and withdrawal from sin is a natural action, not an action which could be rewarded by the kingdom.
If you are a friend of Christ you should have as friends persons who are of benefit to you and contribute to your way of life. Let your friends be men of peace, spiritual brethren, holy fathers. It is of such that our Lord was speaking when He said: 'My mother and brethren are those who do the will of My Father who is in heaven.' (cf. Matt. 12:49-50).
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.
A person standing at an open window hears the sounds from outside; it is impossible not to do so. But he can give the voices his attention or not, as he himself wishes. The praying person is continually beset by a stream of inappropriate thoughts, feelings and mental impressions. To stop this tiresome stream is as impracticable as to stop the air from circulating in an open room. But one can notice them or not. This, say the saints, one learns only through practice.
Join to every breath a sober invocation of the name of Jesus and the thought of death with humility. Both these practices bring great profit to the soul.
Be not forgetful to entertain strangers: for thereby some have entertained angels unawares. (Heb. 13:2) Accepting the task of hospitality, the patriarch [Abraham] used to sit at the entrance to his tent (cf. Gen. 18:1), inviting all who passed by, and his table was laden for all comers including the impious and barbarians, without distinction. Hence he was found worthy of that wonderful banquet when he received angels and the Master of all as guests. We too, then, should actively and eagerly cultivate hospitality, so that we may receive not only angels, but also God Himself. 'For inasmuch,' says the Lord, 'as you have done it to one of the least of these My brethren, you have done it unto Me' (Matt. 25:40). It is good to be generous to all, especially to those who cannot repay you.
True joy is the joy of consolation, the joy that wells up in the knowledge of one's own weakness and the Lord's mercy, and that does not need the bared teeth of laughter to express itself.
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.