Quick answer
The bluntest sentence in the chapter. If you want to know something, you have to be willing to be told you are wrong about it.
Read both lines
The first line makes the two loves inseparable: you cannot want knowledge and refuse the process that delivers it, because correction is how anyone finds out what they had wrong. The second line does not soften. The word rendered "stupid" is a harsh one, closer to brutish, describing an animal's incapacity rather than a low IQ, and the point of the insult is that refusing correction puts a person outside the category of creatures that can learn. This is the same failure the old man at 5:12 confessed to at the end of his life, and the book keeps naming it as the one posture nothing can get past.
Related: Proverbs 5:12 · Proverbs 9:8 · Proverbs 15:32
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.