Likutei Moharan 105:4/ליקוטי מוהר"ן ק״ה:ד׳

14. In addition, I heard that this is the explanation of the verse “O God, pray, heal her, pray!” (Numbers 12:13). On the face of it, the repetition of the word “pray” is quite odd. However, now it is clearly explained. Moshe Rabbeinu, may he rest in peace, asked this of God, that God Himself, as it were, should pray and petition Himself to heal her. Now, how much sweeter than honey is the resolving of this verse.

2Thus this is the meaning of: O God, pray—That is, Moshe Rabbeinu, may he rest in peace, prayed to God. He said to Him: “O God, pray,” and he petitioned and prayed, “You Yourself, to Yourself.”

3heal her, pray—That is, as explained above, Moshe prayed to God and pleaded with Him that He Himself should pray and ask, “Heal her, pray!” Thus now the repetition of the word “pray” is precise, and clearly explained.