The passing of Aaron appears twice in the book of Bamidbar: once in our parasha, Chukat — where his death is told; and again in Parashat Massei, within the list of journeys. This repetition is no accident.

Moses brings Aaron and his son Elazar up Mount Hor, on the border of Edom. There Aaron passes, and “all the house of Israel wept for Aaron thirty days.” Yet here, in Chukat — there is no date.

The fifth month (counting Nissan as first) is Av — and the first of the month is Rosh Chodesh Av. What is remarkable: Aaron is the only figure in the whole Chumash whose date of death is stated outright — not the patriarchs, not Yosef, and even Moses only by a hint.

Parashat Matot-Massei is always read on the Shabbat near Rosh Chodesh Av. So the Torah repeats Aaron’s death in Massei — so that on the Shabbat closest to the day of his passing, we speak of him. That is his remembrance.

Where do we read of Moses near the day of his passing (7 Adar)? In Parashat Tetzaveh — and there, of all places, Moses’ name does not appear, the only parasha since his birth. The midrash: because he said, “Erase me from Your book that You have written.”

A difficulty: Moses said “erase me” in Ki Tisa, which comes after Tetzaveh. The resolution: “from Your book” hints at the book numbered kaf (twenty) — and Tetzaveh is the twentieth parasha from Bereshit. The reward, measure for measure: precisely because his name is absent, every darshan in the world asks “why is Moses missing here?” — and so mentions him near his yahrzeit. The absence is the greatest remembrance of all.

The Second Temple was destroyed on the Ninth of Av because of baseless hatred. Aaron loved peace, pursued peace, and brought people close to Torah. His passing at the start of the month reminds us of the remedy: Aaron’s way is the repair for that hatred. Already on Rosh Chodesh Av the tikkun begins that will bring the Third Temple — and turn Av into a festival.

Seemingly impossible: to place the breastplate on Elazar, he must already be dressed beneath. The Ramban (citing Yalkut Shimoni): a miracle — beneath his garments Aaron was already clothed in “garments of the Shechina,” ready for the World to Come. A second approach: Aaron wore the eight garments (having finished the service) and Elazar four — Moses simply transferred the four special ones (robe, ephod, breastplate, tzitz). The long robe is no problem — it must reach the floor anyway (the bells and pomegranates). His soul was gathered in wholeness.