Students of these revered writings should be advised not only to learn the kinds of expressions in the holy Scriptures, to notice carefully how they are customarily expressed there, and to remember them but also to pray that they may understand them, and this is chiefly and especially necessary. Indeed, in these books which they are studying earnestly, they read that “the Lord gives wisdom; and out of his mouth comes prudence and knowledge.” It is from him that they have received that zeal for study, if it is endowed with piety.
For the Lord gives wisdom. This verse refers to what was said above: For if you call out for wisdom, and so on, until it says: And you will find the knowledge of God. For wisdom, that is, the Lord, is to be invoked to receive wisdom, because wisdom cannot be possessed by us ourselves, but is given by the Lord. Let Pelagius be silent, refuted by the Apostle who says: For what do you have that you did not receive? (1 Cor. IV). And James the Apostle: If anyone lacks wisdom, let him ask of God (James I).
And from his mouth comes wisdom and understanding. In this verse, that ineffable and coeternal wisdom born of God the Father may be understood, of which it is elsewhere said: I came forth from the mouth of the Most High, the firstborn (Eccli. XXIV). The mouth of the Lord can also be understood in his saints, whence it is often said in the prophets, Because the mouth of the Lord has spoken; And from his mouth comes knowledge and understanding, which unless he himself sanctifies the human mouth, unless he graciously makes it his own, no one can speak perfect wisdom.
[AD 430] Augustine of Hippo on Proverbs 2:6