Compunction comes when you consider how much you have grieved God Who is so good, so sweet, so merciful, so kind, and entirely full of love; Who was crucified and suffered everything for us. When you meditate on these things and other things the Lord has suffered, they bring compunction.
As soon as a man becomes humble, mercy is not slow to envelop him. Then the heart is aware of God’s help, and acquires a certain power of assurance (in God) which arises in it. And when a man is aware that God’s help is actually assisting him, his heart becomes filled with faith in very truth.
If a man purifies his heart and uproots from it all sin against the Lord; if he labors diligently to acquire Divine knowledge and succeeds in seeing with his mind that which is invisible to many, he must not through this exalt himself over others. Who among creatures is purer than an incorporeal being and who has more knowledge than an Angel? Yet, having exalted himself he was cast down from heaven like lightning. His pride was regarded by God as impurity.
A small affliction borne for God’s sake is better [before God] than a great work performed without tribulation, because affliction willingly borne brings to light the proof of love.
Just as we must beware of overeating, so too we must beware of excessive temperance or abstinence. Excessive temperance weakens the body, destroys wakefulness, coolness and freshness which are indispensable for vigilance, and which fade and weaken when the physical powers succumb and fail. If you force a weak body to labor beyond its powers, you subject your soul to double darkness, and lead it into confusion (and not relief)...
Even a pious person is not immune to spiritual sickness if he does not have a wise guide -- either a living person or a spiritual writer. This sickness is called prelest, or spiritual delusion, imagining oneself to be near to God and to the realm of the divine and supernatural. Even zealous ascetics in monasteries are sometimes subject to this delusion, but of course, laymen who are zealous in external struggles (podvigi) undergo it much more frequently. Surpassing their acquaintances in struggles of prayer and fasting, they imagine that they are seers of divine visions, or at least of dreams inspired by grace. In every event of their lives, they see special intentional directions from God or their guardian angel. And then they start imagining that they are God's elect, and often try to foretell the future. The Holy Fathers armed themselves against nothing so fiercely as against this sickness -- prelest.