He that walketh with wise men shall be wise: but a companion of fools shall be destroyed.
Multitudes are brought to ruin by bad company. And all that make themselves wicked will be destroyed.
He that walketh with wise [men] shall be wise
Who is a companion of them that fear the Lord; converses frequently with them in private about spiritual and experimental things, and walks with them in public in all the commandments and ordinances of the Lord; he by those means grows wiser and wiser, gains a large stock of spiritual knowledge and experience; for this holds good both in natural and spiritual wisdom, a man of any capacity at all will improve by keeping wise company;
but a companion of fools shall be destroyed;
the Vulgate Latin version renders it, “shall become like them”; be a fool as they are, and grow still more and more foolish. The Septuagint version is, “shall be known”; known by the company he keeps to be a fool also: or rather, “shall be broken”; ruined and destroyed, “evil communications corrupt good manners”, (1 Corinthians 15:33) , and so bring to ruin and destruction.
John Gill’s Exposition of the Bible