Leviticus 10:2

2The Lord suddenly sent fire to completely burn Nadab and Abihu. They died there in front of the Lord's altar.10:2 Nadab and Abihu were the oldest of Aaron's four sons. The Lord had just sent fire to burn the offerings that he accepted. See Leviticus 9:24. Now he sent fire to destroy the priests who did not obey his commands about offerings.