When someone is beginning the spiritual life, he should not study a lot, but instead watch himself and guard his thoughts. A strong person is the one who chews well, not the one who eats a lot.
No Christian believing rightly in God should ever be off his guard. He should always be on the look-out for temptation, so that when it comes he will not be surprised or disturbed, but will gladly endure the toil and affliction it causes, and so will understand what he is saying when he chants with the prophet: 'Prove me, O Lord, and try me' (Ps. 26:2 LXX). For the prophet did not say, 'Thy correction has destroyed me,' but, 'it has upheld me to the end' (Ps. 18:35 LXX).
The heart which is constantly guarded, and is not allowed to receive the forms, images and fantasies of the dark and evil spirits, is conditioned by nature to give birth from within itself to thoughts filled with light. For just as coal engenders a flame, or a flame lights a candle, so will God, who from our baptism dwells in our heart, kindle our mind to contemplation when He finds it free from the winds of evil and protected by the guarding of the intellect.
If you wish that God should speedily give you hearty faith in prayer, strive with all your heart to speak and to do everything in regard to other people sincerely, and never be deceitful in your dealings with them. If you are straightforward and truthful with others, then God will give you straightforwardness and sincere faith also in reference to Himself.
We must accomplish the course of our earthly pilgrimage with the greatest attention and watchfulness over ourselves, unceasingly calling upon God in prayer for help.
Continually take careful note of your inner intention: watch carefully which way it inclines, and discover whether it is for God and the sake of goodness itself and the benefit of your soul...
We must vigilantly guard our heart from unfitting thoughts and impressions, according to the word of the writer of Proverbs: ‘Keep thine heart with the utmost care; for out of these are the issues of life,’ (Proverbs 4:23).
No one can say, 'I am poor and hence I have no means of giving alms.' For even if you cannot give as the rich gave their gifts into the temple treasury, give two farthings as the poor widow did, and from you God will consider it greater gift than the gifts of the rich. And if you do not have as much as two farthings? You can take pity on the sick and give alms by ministering to them. And if you cannot do even this? You can comfort your brother by your words. 'A good word is better than the best of gifts.'
It is impossible for the soul to attain anything spiritual and pleasing to God, or to be free of inner sin, without guarding of the mind and purity of heart, in other words, without sobriety... If with God's help we gain something daily through our sobriety, we should take care not to enter into communication with other people without discrimination, lest we suffer loss through our converse with them and are led into temptation.
Let us go forward with the heart completely attentive and the soul fully conscious. For if attentiveness and prayer are daily joined together, they become like Elias' fire-bearing chariot, raising us to heaven. What do I mean? A spiritual heaven, with sun, moon and stars, is formed in the blessed heart of one who has reach a state of watchfulness, or who strives to attain it.
Watchfulness cleanses the conscience and makes it lucid. Thus cleansed, it immediately shines like a light that has been uncovered, banishing such darkness. Once this darkness has been banished through constant and genuine watchfulness, the conscience then reveals things hidden from us.
Watch constantly, learning to understand God's law, for this warms the heart with heavenly fire. Guard your lips from the idle word, or empty talk, lest the heart gets used to evil words.