Jamieson, Fausset and Brown on Leviticus 10:2

2. there went out fire from the Lord, and devoured them--rather, "killed them"; for it appears (Le 10:5) that neither their bodies nor their robes were consumed. The expression, "from the Lord," indicates that this fire issued from the most holy place. In the destruction of these two young priests by the infliction of an awful judgment, the wisdom of God observed the same course, in repressing the first instance of contempt for sacred things, as he did at the commencement of the Christian dispensation (Ac 5:1-11).