Gregory the Great, on John 14:22

“Judas saith to him, not the Iscariot: Lord, how is it, that thou wilt manifest thyself to us, and not to the world?”

“(Hom. xxx.) Unless the Spirit be present to the mind of the hearer, the word of the teacher is vain. Let none then attribute to the human teacher, the understanding which follows in consequence of his teaching: for unless there be a teacher within, the tongue of the teacher outside will labour in vain. Nay even the Maker Himself does not speak for the instruction of man, unless the Spirit by His unction speaks at the same time.”

Imported from an open dataset — not yet checked against the printed edition.