Quick answer
One man wants without stopping, the other gives without holding back. The verse puts two appetites side by side.
Read both lines
The first line continues verse 25's man and adds duration, all day long, which turns a trait into a condition. The Hebrew doubles the root for desire, wanting a wanting, so the craving has become its own occupation. Then the second line does something unexpected by answering greed with generosity rather than with restraint. The obvious opposite of covetousness would be contentment; the book chooses giving instead, and "does not spare" describes an open hand rather than a careful one. What the pairing suggests is that the cure for a life spent wanting is not learning to want less. It is having somewhere for the wanting to go. The lazy man of the previous verse has hands that refuse; this righteous man has hands that open, and the difference between them is not the strength of the appetite but its direction.
Related: Proverbs 21:25 · Proverbs 11:24–25 · Proverbs 19:17 · Proverbs 22:9
New King James Version®, Copyright © 1982, Thomas Nelson. All rights reserved. Full copyright information. Scripture provided by API.Bible.
Go Deeper
If this verse has been used to put weight on you that it was never carrying, ask about it directly.