Bede

As if a thorn should spring forth in the hand of a drunkard, etc. A thorn springs forth in the hand of a drunkard when, in his works, who serves carnal seductions, the pricks of sins arise. To these rightly is compared a parable which the foolish propose, for although the foolish may know how to utter wise words, they do not know how to avoid the pricks of sins by which they either lacerate themselves or their neighbor. …

Commentary on Proverbs ↗