וַֽיַּחֲרִ֔ישׁוּ וְלֹֽא־עָנ֥וּ אֹת֖וֹ דָּבָ֑ר כִּֽי־מִצְוַ֨ת הַמֶּ֥לֶךְ הִ֛יא לֵאמֹ֖ר לֹ֥א תַעֲנֻֽהוּ׃
But they held their peace, and answered him not a word; for the king’s commandment was, saying: ‘Answer him not.’
Read midrashic interpretation of Isaiah 36:21: and classical rabbinic exegesis.