From the first letter of apostle Paul to Timothy --1:3-7
"I repeat the directions I gave you when I was on my way to Macedonia: stay on in Ephesus in order to warn certain people there against teaching false doctrines and busying themselves with interminable myths and genealogies, which promote idle speculations rather than that training in faith which God requires.
What we are aiming at in this warning is the love that springs from a pure heart, a good conscience, and sincere faith. Some people have neglected these and instead have turned to meaningless talk, wanting to be teachers of the law but actually not understanding the words they are using, much less the matters they discuss with such assurance."
And from St. Gregory the Great in this days Office of Readings, the first paragraph : “A spiritual guide should be silent when discretion requires and speak when words are of service. Otherwise he may say what he should not or be silent when he should speak. Indiscreet speech may lead men into error and an imprudent silence may leave in error those who could have been taught. Pastors who lack foresight hesitate to say openly what is right because they fear losing the favor of men. As the voice of truth tells us, such leaders are not zealous pastors who protect their flocks, rather they are like mercenaries who flee by taking refuge in silence when the wolf appears.”