Musar do Przysłów 27:2

Pride in Wisdom and Good Deeds may be divided into two types — one good and the other bad. The pride that is bad is when a man despises others in his heart and with his mouth, and when all people aside from himself are small and lacking in his eyes, and he constantly praises himself that he is all wise and is therefore often tempted to deny a truth because he is too conceited to admit that he could be wrong. Such a person always believes that his words, advice and deeds are better than the words, advice and deeds of his friends and companions. Such a one boasts constantly of his wisdom and deeds for he desires praise and honor for all the good things he does. And covering this sort of person, Solomon says, "Let a stranger praise you and not your own mouth!" (Prov. 27:2).