וַיָּ֧שֶׂם יְהוָ֛ה דָּבָ֖ר בְּפִ֣י בִלְעָ֑ם וַיֹּ֛אמֶר שׁ֥וּב אֶל־בָּלָ֖ק וְכֹ֥ה תְדַבֵּֽר׃
And the LORD put a word in Balaam’s mouth, and said: ‘Return unto Balak, and thus thou shalt speak.’
Read kabbalistic (mystical) interpretation of Numbers 23:5: and classical mystical sources.