If someone is judged worthy to receive the gift of knowledge but allows his heart to be full of bitterness or rancor or aversion to another, it is as if he had been struck in the eye by a thornbush. That is why knowledge is no good without charity.
If you have received from God the gift of knowledge, however limited, beware of neglecting charity and temperance. They are virtues which radically purify the soul from passions and so open the way of knowledge continually.
What is self-justification? - Self-justification is when a man denies his sin, as we see in the case of Adam, Eve, Cain and others who have sinned but, wishing to justify themselves, denied their sin.
But a sober and prudent man who desires to be saved, when he sees from what it is that he suffers harm, carefully preserves himself from evil remembrances, is not drawn into passionate thoughts, avoids meetings and conversations with those for whom he feels attraction and avoids every occasion for sin, fearing lest he himself ignite a fire within himself. This is the warfare which proceeds from one’s own lust, which a man brings on himself
If you are a friend of Christ you should have as friends persons who are of benefit to you and contribute to your way of life. Let your friends be men of peace, spiritual brethren, holy fathers. It is of such that our Lord was speaking when He said: 'My mother and brethren are those who do the will of My Father who is in heaven.' (cf. Matt. 12:49-50).
If you wish to be delivered from shameful passions, do not behave with anyone familiarly, especially with those toward whom your heart is inclined by a lustful passion; through this you will be delivered also from vainglory. For in vainglory is involved the pleasing of men, in the pleasing of men is involved familiarity of behavior, and familiarity of behavior is the mother of all passions.