After Aaron’s blessing and Moses’ prayer, fire did descend from heaven and consume the parts of the sacrifices that had been placed on the Altar. When the Jewish people saw this, they were ecstatic that G‑d’s presence appeared to them again openly. Their efforts in donating material for the Tabernacle and working diligently in constructing it, as well as their inner “work” of repenting for the incident of the Golden Calf, had born fruit. But then, two of Aaron’s four sons, Nadav and Avihu, offered up some incense on their own initiative. To everyone’s horror, Divine fire again descended, but this time in the form of two pairs of flames that entered Nadav’s and Avihu’s nostrils, killing them instantly.
Managing Ecstasy
וַתֵּצֵא אֵשׁ מִלִּפְנֵי ה' וַתֹּאכַל אוֹתָם וגו': (ויקרא י:ב)
A fire went forth from before G‑d and consumed them. Leviticus 10:2

Nadav and Avihu were swept up in the ecstasy of the moment. In their intense desire to cleave to G‑d, which they expressed through their unauthorized incense offering, they rose through spiritual heights even as they felt their souls leaving them. From this perspective, their death was not a punishment but a fulfillment of their wish to dissolve into G‑d’s essence.

Nevertheless, we are not intended to imitate their example; on the contrary, we are expressly forbidden to pursue such suicidal spiritual rapture. Although it is necessary to seek inspiration and renew it constantly, the purpose of reaching increasingly higher planes of Divine consciousness is to bring the consciousness that we acquire down into the world, thereby making the world increasingly more conscious of G‑d, transforming it into His home.1