Proverbs 17:28 in the King James Version
Even a fool, when he holdeth his peace, is counted wise: and he that shutteth his lips is esteemed a man of understanding.
Context
27 He who spares his words has knowledge. He who is even tempered is a man of understanding.
28 Even a fool, when he keeps silent, is counted wise. When he shuts his lips, he is thought to be discerning.