The fire which had just before sanctified the ministry of Aaron as well pleasing to God, now brought to destruction his two eldest sons because they did not sanctify Yahweh in their hearts, but dared to perform a self-willed act of worship; just as the same Gospel is to one a savor of life unto life, and to another a savor of death unto death 2-Corinthians 2:16.

And there went out fire from the Lord,.... They sinned by fire, and they were punished by fire, either from heaven, or from the most holy place, where the Lord dwelt between the cherubim; this was of the nature of lightning, as appears by what follows:
and devoured them; not reduced them to ashes, for neither their bodies nor their clothes were burnt with this fire, as is clear from Leviticus 10:4 but their lives were destroyed, they were lifeless, their souls were separated from their bodies by it, and they died; which is often the case by the lightning, that the clothes of those who are killed with it are untouched, and scarce any marks of violence on their bodies; and so the Targum of Jonathan says of these, their bodies were not burnt:
and they died before the Lord; upon the spot where they were offering incense, in the holy place, over against the most holy place. This was very awful, like the case of Ananias and Sapphira, and may seem severe: it was for the terror of others in the priesthood, or who should come after, to take care that they performed their office according to the divine precepts, and brought in no innovation into their service. And when it is considered that these were the sons of the high priest, newly invested with an high and honourable office, and just had the laws of the priesthood delivered unto them, and yet deviated from them as soon as in their office, and very probably, from what follows, went drunk into their service, their sin will appear aggravated, and the punishment less severe. This shows there is nothing in carnal descent, these were the sons of Aaron the high priest, that acted this part, and came to this end; the proneness of men to transgress the laws of God as soon as given them; thus the people of Israel fell into idolatry as soon as the moral law was given; and here the priests, as soon as the ceremonial laws, relating to the priesthood, were delivered to them; and also that the law made sinful men priests, and that the Levitical priesthood was imperfect; and that no order of men are free from sin, or exempt from punishment: and the whole of the divine conduct in this affair may lead us to observe how jealous God is in matters of worship; how much he dislikes hypocrites, and formal professors; how severe he will be against such who bring in strange doctrines; what will be the fate of the contemners of Gospel doctrines and ordinances; and how much he resents those who trust in themselves, and their works, and bring in anything of their own in the business of salvation, which is strange fire, sparks of their own kindling, a burning incense to their own drag, and sacrificing to their own net.

there went out fire from the Lord, and devoured them--rather, "killed them"; for it appears (Leviticus 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 (Acts 5:1-11).

From the Lord - From heaven, or rather from the sanctuary. Devoured them - Destroyed their lives; for their bodies and garments were not consumed. Thus the sword is said to devour, 2-Samuel 2:26. Thus lightning many times kill persons, without any hurt to their garments.