A deadly plague broke out among Bnei Yisrael, punishing them for sinning with the daughters of Moav and worshipping their gods. Meanwhile, Zimri, the leader of the tribe of Shimon, publicly took a Midianite princess into his tent. Moshe and the elders were stunned.  Pinchas, remembering what Moshe had taught regarding such a situation, entered Zimri’s tent, caught him in sinning with the non-Jewish woman, and killed him, whereupon the plague miraculously stopped.

What caused Pinchas to remember the law and implement the correct course of action, more so than anyone else present at the time?

The Torah answers this question by highlighting at the very beginning of this episode that Pinchas descended from Aharon (see Bamidbar 25:7).

Aharon, as we know, excelled in his love for another Jew, and persistently sought out their wellbeing. Aharon “pursued peace, and promoted love between disputing parties” (Rashi, Bamidbar 20:29). Aharon daringly demanded from Pharaoh to free Bnei Yisrael from Egypt (see Shemos 6:27). Aharon took the blame for making the Golden Calf, to try to spare Bnei Yisrael from G-d’s wrath (see Rashi, Shemos 32:5). It was in Aharon’s merit that the Clouds of Glory protected Bnei Yisrael in the desert (see Rashi, Bamidbar 20:1).

As a grandchild of Aharon, Pinchas inherited this love for his fellow Jews and this devotion to their good. As the plague took one Jewish life after another, Pinchas frantically searched for a way to stop it. His desperate desire to find a means of saving his fellow Jews caused him to recall a law that everyone else had forgotten, and motivated him to risk his life to implement that law in order stop the plague.

The Torah therefore reiterates that Pinchas was, “the son of Elazar, the son of Aharon the Kohen.” For the source of Pinchas’ profound love for his people, which dictated his thinking processes and drove him to absolute self-sacrifice, was his lineage to Aharon.

—Toras Menachem 5748, vol. 4, pp. 71-75