Gregory the Dialogist

Wherefore have ye detracted from the words of truth; when there is none of you that is able to convict them? He must himself be pure from evil, who makes it his concern to correct the evil practices of other men, so as not to be taken up with earthly imaginations, not to give way to grovelling desires, in order that he may the more clearly see what things others ought to avoid, in proportion as he himself the more thoroughly eschews them by knowledge and by practice. …

Morals on the Book of Job, Book VII ↗

Thomas Aquinas

Not only do they offer him no help, but they even afflict him further with their words as much as they can. So he adds, "Why do you slander true ideas?" which he spoke first in his lamentation and which Eliphaz seemed to reprove as has been said. He disproves all the reasons which can excuse a detractor to justify his conduct to show this detraction is inexcusable. The first of these is the censure someone in greater authority makes of another for a fault. …

Commentary on Job ↗