Комментарий к Бамидбар 33:38

'על פי ה [AND AARON THE PRIEST WENT UP TO MOUNT HOR] BY THE WORD (lit., BY THE MOUTH) OF THE LORD— This phrase tells us that he died by the Divine Kiss (Bava Batra 17a; cf. Rashi on Numbers 20:26).

בחדש החמישי באחד לחודש, “in the fifth month on the first of the month.” This was the New Moon on which Aaron died. On the ninth of that month (many hundreds of years later) the Temple was burned and the Torah with it. On the 7th of the month of Adar following Moses died, as is reported in Joshua that the Children of Israel crossed the river Jordan on the tenth of the first month (Nissan). You may deduct the three days that the people prepared food for the crossing and 30 days during which the people mourned their leader and you will find that Moses must have died on the 7th of Adar (compare Joshua 4,19 and 1,11).

This teaches that he died by the Divine kiss. Meaning: That על פי ה' [lit. "by the mouth of Hashem" is expounded both forward and backward. [One reads backward, teaching] “Aharon ascended by the word of Hashem” and one also reads [forward,] that “By the mouth of Hashem he died there.”