A bridle was very proper and usual for an ass, when they rode upon it, (as the Jews most commonly did,) though not to restrain him from running away, which is the principal use of it in horses, yet that the rider might rule and guide him, which was very necessary for that stupid creature. Although the ancient interpreters render it a goad, or spur, or something of the like nature and use. A rod for the fool's back; which is most proper and necessary for him. Not words, but blows, must make him better.
Related Commentaries of Proverbs 26:3
Proverbs 26:3
3 A whip for the horse, a bridle for the ass, and a rod for the fool's back.