וְעַתָּ֖ה לֵ֑ךְ וְאָנֹכִי֙ אֶֽהְיֶ֣ה עִם־פִּ֔יךָ וְהוֹרֵיתִ֖יךָ אֲשֶׁ֥ר תְּדַבֵּֽר׃
Now therefore go, and I will be with thy mouth, and teach thee what thou shalt speak.’
Read kabbalistic (mystical) interpretation of Exodus 4:12: and classical mystical sources.