Numbers 16:18

“And they took every man his censer, and that fire in them, etc.] That is, they came the next morning, according to order, prepared with their censers and incense; and they took fire from off the altar of burnt offering, which stood in the court of the tabernacle: and laid incense thereon: upon the fire in their censers, and so burned it: and stood in the door of the tabernacle of the congregation; not in the holy place, where the altar of incense was, for that would not hold them; nor indeed in the court of the tabernacle, but at the door of it, or the outside of it, that so they might be seen by all the people who came to be spectators and witnesses of this affair: and they stood with Moses…”

“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. Numbers 16:19”

“16:18-22 At the height of the insurrection, the Lord intervened to save Moses and Aaron, and they interceded for the people.”

“The next day the rebels presented themselves with censers before the tabernacle, along with Moses and Aaron; and the whole congregation also assembled there at the instigation of Korah. The Lord then interposed in judgment. Appearing in His glory to the whole congregation (just as in Num 14:10), He said to Moses and Aaron, "Separate yourselves from this congregation; I will destroy them in a moment." By assembling in front of the tabernacle, the whole congregation had made common cause with the rebels. God threatened them, therefore, with sudden destruction. But the two men of God, who ere so despised by the rebellious faction, fell on their faces, interceding with God, and praying, "God,…”