The censers of the two hundred fifty men who had sinned against their souls, that is, against themselves, were made into hammered plates as a covering for the altar, as a sign to the sons of Israel and a reminder to them, so that no one who was a stranger, who was not of the descendants of Aaron, would draw near to burn incense before Jehovah, lest he become as Korah and as his company (vv. 36-40). The two hundred fifty men were burned by God in His judgment. Then their censers were hammered into plates to cover the altar. When the people came to offer at the altar, they were reminded of the rebellion and of God's judgment on Korah and his company.
We may think that, after this twofold judgment, all the children of Israel would be calmed down and subdued. That, however, was not their situation. Their rebellious nature remained in them, and it was exposed. In verses 41 through 50 we have the exposure of the unsubdued rebellious nature of the children of Israel.
The murmuring of the people against Moses and Aaron proves that their rebellious nature had not been subdued. "On the next day all the assembly of the sons of Israel murmured against Moses and against Aaron, saying, You have killed the people of Jehovah" (v. 41). I find it incredible that they could murmur against Moses and Aaron in such a way.
God intervened immediately. His glory appeared in the cloud that covered the tent of meeting (v. 42). He told Moses that He would consume the assembly in a moment (vv. 43-45a), and He sent the plague to kill them under His wrath (v. 46b). The germs of the plague were probably in them already.