I should like to add that Isaac the Syrian insists on penitence, necessary alike for those who are conscious of sinning greatly and for those who are not; there is no perfection in any of us here on earth. The true signs of sincere penitence are the taming of the beast of anger, and the abstinence from all condemnation of others. Anger is always a sign of great pride. Our Lord calls him who condemns others, oblivious of his own faults, a hypocrite.

Letters of Elder Macarius of Optina