Bede, on Prov 26:8

“As he that casteth a stone into the heap of Mercury: so is he that giveth honour to a fool.”

“As he who casts a stone into the heap of Mercury, etc. He who grants the honor of teaching to the foolish, that is, to the heretic, sins no less than he who worships the gods and idols of the pagans in vain.”

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