Numbers 22:34

כי לא ידעתי FOR I KNEW NOT — This statement, too, (cf. v. 29), was a disgrace for him, for in spite of himself he had to admit it — because he used to boast that he knew the will of of the Most High (24:16) and now his own mouth bore testimony: “I knew not” (Midrash Tanchuma, Balak 10). אם רע בעיניך אשובה לי IF IT BE EVIL IN THINE EYES, I WILL RETURN — To set himself in opposition to the Omnipresent was the purpose of this reply. He said, in effect, “He Himself commanded me to go, and you, angel, annul His words. He is accustomed to this — that He says something and an angel recalls it. He said to Abraham, (Genesis 22:2) Take now thy son, etc.’ and by an angel annulled His words. I, too: "If it be evil in thine eyes, then I must return” (Midrash Tanchuma, Balak 10).

וַיֹּ֨אמֶר בִּלְעָ֜ם אֶל־מַלְאַ֤ךְ יְהֹוָה֙ חָטָ֔אתִי כִּ֚י לֹ֣א יָדַ֔עְתִּי כִּ֥י אַתָּ֛ה נִצָּ֥ב לִקְרָאתִ֖י בַּדָּ֑רֶךְ וְעַתָּ֛ה אִם־רַ֥ע בְּעֵינֶ֖יךָ אָשׁ֥וּבָה לִּֽי׃

And Bil῾am said to the angel of the Lord, I have sinned; for I knew not that thou didst stand in the way against me: now therefore, if it displease thee, I will get me back again.