Matthew Henry and continuators on Proverbs 26:3

3 A whip for the horse, a bridle for the ass, and a rod for the fool's back.

Here, 1. Wicked men are compared to the horse and the ass, so brutish are they, so unreasonable, so unruly, and not to be governed but by force or fear, so low has sin sunk men, so much below themselves. Man indeed is born like the wild ass's colt, but as some by the grace of God are changed, and become rational, so others by custom in sin are hardened, and become more and more sottish, as the horse and the mule, Ps. xxxii. 9. 2. Direction is given to use them accordingly. Princes, instead of giving honour to a fool (v. 1), must put disgrace upon him—instead of putting power into his hand, must exercise power over him. A horse unbroken needs a whip for correction, and an ass a bridle for direction and to check him when he would turn out of the way; so a vicious man, who will not be under the guidance and restraint of religion and reason, ought to be whipped and bridled, to be rebuked severely, and made to smart for what he has done amiss, and to be restrained from offending any more.