For in much wisdom is much grief: and he that increases knowledge increases sorrow.
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Augustine of Hippo
People are accustomed to set a high value on the knowledge of earthly and celestial things. But they are certainly better who prefer the knowledge of themselves to this knowledge. And a mind to which even its own weakness is known is more deserving of praise than one that … is ignorant of the course by which it must proceed to reach its own true health and strength. But one who has been aroused by the warmth of the Holy Spirit … has already awakened to God. In his love for [God, such a person] has already felt his own unworthiness and is willing but is not yet strong enough to come to him. And through the light received from [God, this person] takes heed to himself and finds that his own defilement cannot mingle with his purity. [This person] feels it sweet to weep and to beseech God that he may again and again have pity until he has cast off all his misery. [This person also prays] with confidence as having already received the free gift of salvation through his only Savior and enligh...
It is evident, then, that the oldness of the letter, in the absence of the newness of the spirit, instead of freeing us from sin, rather makes us guilty by the knowledge of sin. [Thus] it is written in another part of Scripture, “He that increases knowledge, increases sorrow.” [It is] not that the law is itself evil, but because the commandment has its good in the demonstration of the letter, not in the assistance of the spirit. And if this commandment is kept from the fear of punishment and not from the love of righteousness, it is kept in a servile manner, not freely, and therefore it is not kept at all. For no fruit is good which does not grow from the root of love.
Labour: He is bound to do more for heaven, as he is convinced of his own defects, and of the strict judgments of God. Wisdom is not true happiness, but the means to obtain it. (Worthington)
The more a person knows, the more he is convinced of his own ignorance, (Calmet) and filled with grief, that wisdom should be so much concealed. (St. Jerome)
Those who are learned, feel indignant that their disciples should be so dull. (Menochius)