Professor N.E. Pestov. "Modern practice of Orthodox virtue".
The beginning of delusion can be determined on the following grounds:
1) Self-confidence, following own will, 
unwillingness to subordinate own will to the elder or spiritual father 
and to the authority of the Church’s consciousness.
2) Self-direction – also called 
"self-centeredness" or "autoeroticism" – is egoism with lack of love, 
gentleness and forbearance to the surrounding people (except, perhaps, 
the closest family members).
3) Keeping the attention on certain 
statements (thoughts) of the spiritual sphere; the deluded people are 
mainly guided in life by these thoughts, ignoring the basic commandments
 of God and the teachings of the Church. These ideas can be taken from 
the Holy Scriptures, but they are isolated from the general spirit of 
the Holy Gospel. Then they divert the deluded person from the main 
virtues - love, humility, obedience and gentleness.
How to protect yourself from delusion:
1) It is obvious that the most radical 
remedy is to be in obedience to the elder or spiritual father, and if 
one can not have them – then to be guided by the views and advice of 
those Christians who succeeded in spiritual wisdom.
2) At the same time, each Christian must study the Scriptures and the works of the Holy Fathers of the Church.
3) Everybody should be keep from having opinions that do not agree with the general church consciousness.
4) We should always be sensitive to the 
views of friends and associates, be attentive to their judgments and 
carefully analyze our disagreements with them. We should remember that 
the Lord often rebukes us through the mouth of our loved ones.

