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 o…

As a thorn goeth up into the hand of a drunkard.—Rather, (As) a thornbush (which) comes in…

As a thorn goes up into the hand of a drunkard
And he does not perceive it; or being in his hand he makes an ill use…

Fools are not fit to be trusted, nor to have any honor. Wise sayings, as a foolish man delivers and applies them, lose their usefulness.