As a thorn goeth up into the hand of a drunkard. There is here no idea of the drunkard's hand being pierced with a thorn while he is insensible to the pain, but rather of his being armed with it, and ripe for mischief.
So it is best to render, "A thornbush cometh into the hand of a drunkard;" he somehow gets possession of it, and in his stupid excitement is liable to become dangerous. Some understand עלה of the growth of the thorn; thus the Septuagint, "Thorns grow in the hand of a drunkard;" Vulgate, "As if a thorn grew in the hand of a drunkard."
But one does not see the bearing of such an expression; and the translation given above is more appropriate. So is a parable, etc. (as Proverbs 26:7). In that passage the wise saying in a fool's mouth was compared with something useless, here it is compared with something injurious.
He employs it purposely to wound others; or by the ignorant use of some sharp-edged word he does much mischief. In this hemistich the LXX. has read משל with a different vocalization, and renders, "servitude ( δουλεία) in the hand of fools."
This seems to mean that it comes natural to fools to be manacled and restrained by force.