Seest thou a man wise in his own conceit? (Proverbs 3:7). Nothing so shuts the door against improvement as self-conceit. "Woe unto them," says Isaiah (Isaiah 5:21), "that are wise in their own eyes, and prudent in their own sight."
Such persons, professing themselves wise, become fools (Romans 1:22; Romans 12:16; Revelation 3:17, Revelation 3:18). Touching conceit, Qui sibi sapit, summe desipit. The Oriental speaks of the fox finding his shadow very large, and of the wolf when alone thinking himself a lion.
There is more hope of a fool than of him (Proverbs 29:20). A fool who is conscious of unwisdom may be set right; but one who fancies himself perfect, and needing no improvement, is beyond cure; his case is hopeless.
So the sinner who feels and acknowledges his iniquity may be converted; but the self-righteous Pharisee, who considers himself to have no need of repentance, will never be reformed (see Matthew Luke 15:7; Luke 18:14).
St. Chrysostom (Hom. in Phil.,' 7), "Haughtiness is a great evil; it is better to be a fool than haughty; for in the one case the folly is only a perversion of intellect, but in the other ease it is still worse; for it is folly joined with madness.
The fool is an evil to himself; but the haughty man is a plague to others too. One cannot be haughty-minded without being a fool … The soul which is puffed up has a worse disease than dropsy, while that which is under restraint is treed from all evil" (Oxford transl.
).