גַּ֤ם אֱוִ֣יל מַ֭חֲרִישׁ חָכָ֣ם יֵחָשֵׁ֑ב אֹטֵ֖ם שְׂפָתָ֣יו נָבֽוֹן׃
Even a fool, when he holdeth his peace, is counted wise; And he that shutteth his lips is esteemed as a man of understanding.
Read midrashic interpretation of Proverbs 17:28: and classical rabbinic exegesis.