Quick answer
The wise are acquirers: heart and ear both stay in the market for knowledge, because wisdom is not a diploma but an appetite.
Read both lines
The verse assigns the same project to two organs: the heart acquires, the verb of active obtaining, and the ear seeks, the verb of the hunt. Notice who is doing this: the prudent and the wise, the people with the most knowledge in the room already. That is the verse's quiet joke and its point. The wise seek knowledge, which is how they got wise and why they stay that way; the fool of 18:2 already knows everything, which is how he got that way too. Growth belongs to whoever still has their ear out the door.
Related: Proverbs 1:5 · Proverbs 9:9 · Proverbs 25:2
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.