Doing Your Way and Not God's Way
Nadad and Abihu, the sons of Aaron, took either of them his censer, and put fire therein, and put incense thereon, and offered strange fire before the Lord, which the Lord commanded them not. And there went out fire from the Lord, and devoured them, and they died before the Lord. (Leviticus 10:1-2).
They tried to do it their way and not God’s way.