R. Yonah #1: Wise Ashirim store silver, gold and oil. The silver and gold are hidden, and the oil is like merchandise with them in the house. They buy it cheaply and sell it expensively ¹ . Chazal said (Bava Metzi'a 42a) to divide one's money in three - a third in land, a third in merchandise and a third available [to spend].

R. Yonah #2: This comes to teach "b'Tzel ha'Chachmah b'Tzel ha'Kasef" (Koheles 7:12). When a Chacham engages to make wealth, he succeeds. One who engages in Torah, his property will succeed - "[v'Hagisa Bo Yomam va'Lailah...] Az Tatzli'ach Es Derachecha v'Az Taskilu" (Yehoshua 1:8; Avodah Zarah 19b).

Malbim (according to the Mashal): A Chacham does not lose his stored wealth and storehouse. He guards it, until a desired storehouse, like gold and fragrances, and good oil ² are found in his dwelling.

Malbim (according to the Nimshal): If this refers to a physical storehouse and oil, a Chacham thinks how it will remain forever in his dwelling. He gives Tzedakah to Aniyim and does Chesed; this remains for him forever. (King Munvaz opened his ancestors' storehouse in famine years to feed the poor. His family protested.) He answered, they stored below; I stored above. They stored where [others'] hands might take it

Rashi: It is a person's folly.

R. Yonah #1: One who wastes his money is a fool in people's eyes. All commoners agree about this.

R. Yonah #2: One who is drawn after physicality and the Yesod Admas Afar in it; he pursues pleasures. The verse teaches that one should put the exertion of his Nefesh and intent to straighten his son and bequeath to him Chachmah. If he will bequeath to him wealth and he is an Evvil, he does not bequeath to him anything, for he will swallow (squander) his storehouses in his folly. Fathers do not bequeath to their sons anything more important than Chachmah, for one acquires wealth via Chachmah, and loses it via folly. Above (19) discussed an evil wife. Our verse discusses a Ben Kesil, and warns one to distance as much as possible from an evil wife, and to rebuke his son and teach to him Chachmah - "Havos l'Aviv Ben Kesil v'Delef Tored Midyenei Ishah" (19:13).

R. Yonah: If he leaves a Ben Kesil [in his way], he will be drawn after Simchah and pleasures, and consume the storehouse that was gathered with Chachmah.

Malbim: He keeps it for himself. In the end, strangers will inherit his wealth, and nothing will remain for him after his death.

Malbim (according to the metaphor): A Kesil is estranged from the laws of Chachmah, due to his desire. He will swallow the storehouse and destroy it. Verse 21 explains what is the storehouse and oil.