Leviticus 9:24-10:1

ASV(i) 24 And there came forth fire from before Jehovah, and consumed upon the altar the burnt-offering and the fat: and when all the people saw it, they shouted, and fell on their faces.
10 1 And Nadab and Abihu, the sons of Aaron, took each of them his censer, and put fire therein, and laid incense thereon, and offered strange fire before Jehovah, which he had not commanded them.