Invective may be a sharp weapon, but overuse blunts its edge. Even when the denunciation is just and true it is an error of art to indulge it too long. [ Tyndall ]

So near are the boundaries of panegyric and invective, that a worn-out sinner is sometimes found to make the best declaimer against sin. The same high-seasoned descriptions which in his unregenerate state served to inflame his appetites, in his new province of a moralist will serve him (a little turned) to expose the enormity of those appetites in other men. [ Lamb ]