Aliya Summary: At this point a heavenly fire descends and consumes the offerings on the altar. Aaron’s eldest two sons, Nadav and Avihu, bring an unauthorized incense offering and a heavenly fire consumes them. Moshe orders the removal of their bodies from the Tabernacle, and instructs Aaron and his remaining two sons not to observe the traditional laws of mourning, considering that they had to continue serving in the Sanctuary on behalf of the Jewish nation. The priests are instructed not to imbibe wine before performing Temple service.
Two of the many “traditions” as to what Nadav and Avihu did wrong are that they decided a point of halacha on their own (to bring an offering) in the presence of their “rebbi” (Moshe), and that they did not consult with anyone in this halachic matter. It behooves us to learn a sobering (purposeful choice of the word) lesson from all of the possible flaws in the actions of Nadav and Avihu. One must be careful when making decisions for oneself and their family. Consulting a Rabbi is a good idea.