Related:

• Answer a fool according to his folly. -- Old Testament -- Proverbs xxvi, 5
• Answer a fool according to his folly, lest he be wise in his own conceit. -- Proverbs, 26:5
• A fool finds no pleasure in understanding but delights in airing his own opinions.
  Miscellaneous Proverb...
• A fool shows his annoyance at once, but a prudent man overlooks an insult. Miscellaneous Proverb
• As a dog returns to his vomit, so a fool returneth to his folly.
  Seest thou a man wise in his own conceit? There is more hope of a fool than of him....
• A fool finds pleasure in evil conduct, but a man of understanding delights in wisdom.
  Miscellaneous Proverb...
• If A fool persists in his folly he shall become wise. -- William Blake
• Even a fool is thought wise if he keeps silent, and discerning if he holds his tongue.
  Miscellaneous Prove...