Concerning Pride ( The Salvation of Sinners )

The more you boast and gloat in your accomplishments, the more you will be disdained and ignored by God, Who opposes the proud, and Who disperses the minds and hearts of all who are conceited: “He has scattered the proud in the imagination of their hearts” (Lk. 1:51).

Humility is the greatest of all gifts; conversely, pride stands as an obstacle to all good things, and it serves as the root of all transgressions.
In order for this evil to be cured, the Lord oftentimes permits us to fall into grave
mistakes and commit serious sins. Our all-wise Physician would certainly not permit this to take place if pride was not the worst and most
severe of all wrongdoings. The Prophet and King David once asserted pridefully, “I said in my prosperity I will never be shaken” (Ps.29:7);
that is to say, “I will not sin.” And so, in order to humble him and cure him of this pride, the Lord consequently permitted the prophet to commit adultery and murder.

 When the Lord foretold the Apostles that they would all abandon Him and flee as soon as the Jews apprehended Him, the Apostle Peter boasted in this manner: “Even if all the other Apostles abandon You, I will never leave you even if I have to lay down my life for Your love.”
(cf. Mt. 26:33-35).

On account of this haughtiness, the Lord permitted Peter to deny Him three times, so that he may subsequently humble himself, lament his weakness, and no longer think highly of himself. Similarly, many virtuous hermits dwelling in the desert, who cast out demons from people and
performed awesome signs and miracles later fell into grave and terrible sins. 

Whoever reads such accounts will be startled and certainly humble himself wholeheartedly.
Since the Lord permits people to fall into such
sins in order to cure their pride, it is obvious that pride is the worst of all sins. Oftentimes, God
also permits people to be falsely accused and slandered for crimes they have not committed in order to make them more humble. Additionally, He may send them various sorrows so that they do not end up becoming prideful, just as the Apostle Paul attests: “There was given to me an angel of
Satan to flog me, so that I do not boast on account of the many revelations I have received”
(cf. 2Cor . 12:7).

from the book
The Salvation of Sinners

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