Spendeth it up - literally, swalloweth it. The wise man keeps a store in reserve. He gains uprightly, spends moderately, never exhausts himself. But the proverb may have also a higher application. The wise man stores up all “treasure to be desired” of wisdom, all “oil” of divine influence, which strengthens and refreshes, and so is ready at all times for the work to which the Master calls him. Compare Matthew 25:1-13.
Related Commentaries of Proverbs 21:20
Proverbs 21:20
20 There is treasure to be desired and oil in the dwelling of the wise; but a foolish man spendeth it up.