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.
Nothing is more unsettling than talkativeness and more pernicious than an unbridled tongue, disruptive as it is of the soul’s proper state. For the soul’s chatter destroys what we build each day and scatters what we have laboriously gathered together.
The proof of authenticity of the spiritual condition of a father confessor is, that while he is very strict with himself, he is very lenient with others and does not use the canons of the Church like cannons against them.
The lower you descend, the higher you ascend; and when, like the psalmist, you regard yourself as nothing before the Lord (cf. Ps. 39:5), then imperceptibly you will grow great. And when you begin to realize that you have nothing and know nothing, then you will become rich in the Lord through the practice of the virtues and spiritual knowledge.