וַיַּ֖עַן וַיֹּאמַ֑ר הֲלֹ֗א אֵת֩ אֲשֶׁ֨ר יָשִׂ֤ים יְהוָה֙ בְּפִ֔י אֹת֥וֹ אֶשְׁמֹ֖ר לְדַבֵּֽר׃
And he answered and said: ‘Must I not take heed to speak that which the LORD putteth in my mouth?’
Read midrashic interpretation of Numbers 23:12: and classical rabbinic exegesis.