(Lev. 10:1-2) “1 Nadab and Abihu, the sons of Aaron, each took his censer, and put fire in it, and laid incense on it, and offered strange fire before Yahweh, which he had not commanded them. 2 Fire came out from before Yahweh, and devoured them, and they died before Yahweh.”
What is the “strange fire”? I think one of the interpretations of this are “motivational speech” in the church. God does not want our ministry to the Lord be motivated by anything that the fire from Holy Spirit. Motivating it by something other leads to spiritual death.