Train yourself to cut off an intrusive thought immediately… Be at pains over this, so that you acquire the habit. The soul is a creature of habit: according to the habit you have acquired, so will you act all the rest of your life.
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.
Since self-love is the origin and mother of evil, when this is eradicated all the things which derive from it are eradicated as well. For when self-love is absent, not the slightest trace or form of evil can exist in any way at all.
It is impossible for the soul to be liberated from turbulent thoughts without the virtue of non-possessiveness. And without peace of the bodily senses it is impossible for the soul to have a peaceful intellect. And if it does not come into temptations it will not acquire wisdom of the Holy Spirit. And without laborious and persistence in reading, it will not come to the discernment of thoughts. And without the stillness of thoughts, the intellect cannot move to seek the hidden mysteries of God.
In his famous book, 'The Ladder', St John Climacus records the life of this saint. The young Acacius was a novice with an evil elder in the monastery on Sinai. The foul-tempered elder daily groused and grumbled at Acacius, and often beat him, tormenting and ill-treating him in every possible way. Acacius did not complain, but bore it all patiently and with trust that it would work for his salvation. When anyone asked him how he survived, he replied : 'Well, as before the Lord God'. After nine years of obedience and ill-treatment, Acacius died. The elder buried him and then went off to lament to another elder, a holy man, saying: 'Acacius, my disciple, is dead. 'I don't believe it' replied the holy elder , 'Acacius is not dead.' They then both went to the dead man's grave, and the holy elder called out: 'Brother Acacius, are you dead?' The obedient Acacius, obedient even in death, replied: 'I am not dead; the obedient cannot die.' Then the evil elder repented and shut himself in a cell near Acacius's grave, where he spent the rest of his life in repentance and prayer.
There is no venom more poisonous than that of the asp or cobra, and there is no evil greater than that of self-love. The winged children of self-love are self-praise, self-satisfaction, gluttony, unchastity, self-esteem, jealousy and the crown of all these, pride. Pride can drag down not men alone, but even angels from heaven, and surround them with darkness instead of light.
Let us, therefore, not flinch from fighting the good fight on behalf of the truth, nor, in despair, fling away from labors we have already achieved. For the strength of the soul is not shown by one brave deed, nor yet by effort only for a short time; but He Who tests our hearts wishes us to win crowns of righteousness after long and protracted trial. Only let our spirit be kept unbroken, the firmness of our faith in Christ be maintained unshaken, and ere long our Champion will appear; He will come and will not tarry. Expect tribulation after tribulation, hope upon hope; yet a little while; yet a little while. Thus the Holy Ghost knows how to comfort His nurslings by a promise of the future. After tribulations comes hope, and what we are hoping for is not far off, for let a man name the whole of human life, it is but a tiny interval compared with the endless age which is laid up in our hopes.
A truly intelligent man has only one care -- wholeheartedly to obey Almighty God and to please Him. The one and only thing he teaches his soul is how best to do things agreeable to God, thanking Him for His merciful Providence in whatever may happen in his life. For just as it would be unseemly not to thank physicians for curing our body, even when they give us bitter and unpleasant remedies, so too would it be to remain ungrateful to God for things that appear to us painful, failing to understand that everything happens through His Providence for our good. In this understanding and this faith in God lie salvation and peace of soul.
Obedience is necessary not only for monks, but for all people. Even the Lord was obedient. Proud and self-assured do not let grace reside within them, and therefore they never have internal peace, whereas the soul of the obedient easily accepts the grace of the Holy Spirit, bringing with it joy and serenity.
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.
Nothing that happens to us is contrary to the will of Providence, and everything that is sent us by God is for our good and the salvation of our soul. Even if it does not seem helpful at the moment, we shall understand later on that it was willed so by God, and that it is not what we ourselves wish that is always useful to us. God sends trials out of his Mercy, so that after we have suffered, we may be crowned by Him. Without temptation it is impossible to receive a crown. This is why we should thank God for these sufferings, as out Benefactor and Savior.
Therefore silence, prayer, obedience; when you practice these virtues with the help of God, then you will know the light of Christ is within your soul.