Proverbs 23:12 (NIV)
Apply your heart to instruction and your ears to words of knowledge.
This admonition is found all through the proverbs. It is vitally important for a person to be docile and open to instruction. Applying the heart means putting your mind seriously to the task of learning how to live a godly way of life. Applying the ears means listening very carefully. Nothing about this says that it is easy. It takes diligence, effort. And it takes application; as the book of James admonishes, "be doers of the word and not hearers only".
There is a reward:
2 Timothy 3:15b (NIV)
You have known the holy Scriptures, which are able to make you wise for salvation through faith in Christ Jesus.