Albert Barnes 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)

Better: As a thorn which is lifted up in the hand of the drunkard etc. As such a weapon so used may do mischief to the man himself or to others, so may the sharp, keen-edged proverb when used by one who does not understand it.