16:18 Fire - Taken from the altar which stood in that place, for Aaron might not use other fire. And it is likely the rememberance of the death of Nadab and Abihu deterred them from offering any strange fire.
16:16-22 The same glory of the Lord that appeared to place Aaron in his office at first, Le 9:23, now appeared to confirm him in it; and to confound those who set up against him. Nothing is more terrible to those who are conscious of guilt, than the appearance of the Divine glory. See how dangerous it is to have fellowship with sinners, and to partake with them. Though the people had treacherously deserted them, yet Moses and Aaron approved themselves faithful shepherds of Israel. If others fail in their duty to us, that does not take away the obligations we are under to seek their welfare. Their prayer was a pleading prayer, and it proved a prevailing one.