Proverbs 26:28 - Joseph Benson’s Commentary on the Old and New Testaments

A lying tongue hateth, &c. That is, he who slanders others hates those whom he slanders, because, by his calumnies, he hath made them his enemies. For “it is common for men to hate those to whom they have done evil: thus Tacitus, Proprium humani ingenii est, odisse quem læseris, ‘It is natural to man to hate one whom he hath injured;' and this aversion is always strong in proportion to the greatness and injustice of the wrong which has been done.” See Calmet. And a flattering mouth worketh ruin Though it be more smooth and plausible than a slandering mouth, yet it is, in truth, no less pernicious, betraying others either to sin, or to danger and calamity.