Parshas Sh’mini presents the shocking sin and deaths of Nadav and Avihu. The pasuk describes how, during the Chanukas HaMishkan (Inauguration of the Tabernacle), Nadav and Avihu offered the k’tores (spice offering) and were engulfed by Divine flames (VaYikra 10:1-2). This episode is both striking and perplexing, as the p’sukim do not clarify what their sin was, or why it warranted such a harsh punishment. At face value, one might think that they acted righteously, sacrificing an offering to Hashem in the Mikdash. What, then, was so egregious about their actions? We will go through a range of possible answers to these questions as we ultimately develop a deeper understanding of this topic.