Charles Ellicott Commentary Proverbs 26:9

"[As] a thorn that goeth up into the hand of a drunkard, So is a parable in the mouth of fools." — Proverbs 26:9 (ASV)

As a thorn goeth up into the hand of a drunkard.—Rather, (As) a thornbush (which) comes into the hand of a drunkard, so (is) a parable (which comes) into the mouth of fools. They do not know how to use it, and only do themselves and others harm by it (Compare to 2 Peter 3:16).