Nadav and Avihu were arrogant and coveted authority; ultimately, they died untimely deaths.

Moses and Aaron were walking on their way, and Nadav and Avihu were walking behind them, and all the Israelites were walking behind Nadav and Avihu. Nadav said to Avihu: When will these two old men die so that you and I will lead the generation? The Holy One, blessed be He, said to them: We will see who buries whom. (Sanhedrin 52a)