Proverbs 26:5-7

Amplified Bible

⁵ 
Answer [and correct the erroneous concepts of] a fool according to his folly,
Otherwise he will be wise in his own eyes [if he thinks you agree with him].^(A)
6 
He who sends a message by the hand of a fool
Cuts off his own feet (sabotages himself) and drinks the violence [it brings on himself as a consequence].^(B)
7 
Like the legs which are useless to the lame,
So is a proverb in the mouth of a fool [who cannot learn from its wisdom].