Leo the Great

To deceive the first human beings, the devil claimed the serpent as his tool. So to seduce the hearts of orthodox, he armed the tongues of these with the poison of his falsehood. With pastoral care, however, we oppose these snares, dearly beloved, to the extent that the Lord helps us. To prevent any of the holy flock from perishing, we advise you with fatherly admonitions to turn away from "wicked lips and treacherous tongue," from which the prophet asks that his soul "be kept free," since "their talk crawls like a crab," as the blessed apostle said. They creep in low to the ground, take hold softly, squeeze gently and kill undetected.