NET
9 Give instruction to a wise person, and he will become wiser still; teach a righteous person and he will add to his learning.
Darby
9 Impart to a wise [man], and he will become yet wiser; teach a righteous [man], and he will increase learning.
KJV
9 Give [instruction] to a wise [man], and he will be yet wiser: teach a just [man], and he will increase in learning.