John Gill, on Prov 8:19

My fruit is better than gold, yea, than fine gold,.... This is said in allusion to the fruit that grows on trees, Wisdom, or Christ, being a tree of life; see Gill on Pro 3:18; and so he is compared to other trees, Sol 2:3. His "fruit" are the blessings of grace, such as redemption, reconciliation, pardon, justification, adoption, and eternal life; these are his by covenant, are procured by him, and are communicated from him; also the graces of his Spirit called fruits, as faith, hope, love, &c. of which he is the author and object; and even good works, the fruits of his grace; they are done in virtue of union to him, by his strength, and are directed to his glory: and all these, especially his grace and the blessings of it, are preferable to the finest gold; they are more valuable as to their intrinsic worth and excellency; they are more useful and profitable, being for the good and welfare of immortal souls; and they are more satisfying and more lasting, and which cannot be obtained with such a corruptible thing as gold is; and my revenue than choice silver; as the former word refers to fruits that grow on trees, this to such as spring from seed sown in the earth; see Lev 23:39, where the same word is used as here, and is also rendered "revenue" in Jer 12:13; Christ himself is compared to seed, and so his word, Joh 12:24; and the fruit or revenue thereof is the same as before: or else the allusion is to the profit arising from riches, from estates, and their annual rent; or from money put out to use, or improved by commerce, and so signifies the same with the gain and merchandise of wisdom; see Gill on Pro 3:14. Aben Ezra construes the words thus, "my revenue is choicer than silver"; but our version is best.