Gregory the Dialogist

As in a house, when the door is shut, it is not known what members there are hidden within, so, generally speaking, if a fool hold his peace, it is hidden whether he be wise or foolish, only, however, if no other works come to light, which may speak the mind even of one that is silent. For this reason the holy man, seeing that his friends were anxious to appear what they were not, charged them to hold their peace, that they might not appear what they were. …

Morals on the Book of Job 11.35 ↗

John Cassian

It belongs to the understanding to discern the distinctions and the drift of questions; and it is a main part of knowledge to understand how ignorant you are. Wherefore it is said that "if a fool asks questions, it will be accounted wisdom," because, although one who asks questions is ignorant of the answer to the question raised, yet as he wisely asks, and learns what he does not know, this very fact will be counted as wisdom in him, because he wisely discovers what he was ignorant of.

Conference 4:9 ↗

Bonaventure

So great is the closeness between silence and wisdom that "the fool, if he keeps silent, will be reputed wise:" and the wise man who speaks much is reputed a fool. In a single word one can utter a detraction; for this reason one must "make a balance for one's words." Immoderation of speech is to be guarded against in the highest degree.

Collationes de Septem Donis, Collation 9 ↗