Quick answer
Understanding refreshes its owner from within, a private spring keeping a life green. The fool's instructional economy is closed: folly teaching folly.
Read both lines
The wise get the image of a wellspring, water rising on your own land, life that does not depend on the rains: understanding is portable, renewable, interior. The second line is compressed enough that its exact sense is debated, the discipline fools dispense, or the schooling their own folly gives them, but either way it lands in the same place: correction that corrects nothing. Set beside the wellspring, the picture is a man with no water on his land drinking from the one contaminated barrel he owns.
Related: Proverbs 13:14 · Proverbs 14:24 · John 4:14
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.