A spiritual guide…

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.
–Saint Gregory the Great (c. 540-604)

Spare the faith…

Whosoever you are who introduce new doctrines, I beseech you to spare the ears of Romans! Spare that faith which was commended by the voice of an Apostle. Why should you attempt to teach us, at the end of hundreds of years, that which we never heard before? Why bring forward what Peter and Paul did not will to make known? Until this day, the world was Christian without your doctrine. Thus, I hold as an old man onto that faith wherein I was regenerated as a boy.
–Saint Jerome (c. 340-420)