Peter Pett's Commentary on the Bible
Numbers 16:36-40
The Metal of the Censers to be Used to Cover the Altar (Numbers 16:36).
‘And Yahweh spoke to Moses, saying,'
“ Speak to Eleazar the son of Aaron the priest, that he take up the censers out of the burning, and you scatter the fire yonder; for they are holy, even the censers of these sinners against their own lives. And let them be made beaten plates for a covering of the altar, for they offered them before Yahweh, therefore they are holy; and they shall be a sign to the children of Israel.”
Having been used in the worship of Yahweh, even by such false ‘priests', the censers and the fire in them were holy. They could not just be tossed away or destroyed. They had been offered before Yahweh and were therefore ‘holy'. But nor could they again be used. So they were told that they must scatter the burning ashes ‘yonder' (on the brazen altar?), and that Eleazar must take the censers of the men who had given their own lives in order to use them, and make of them beaten plates which could be used as a covering for the altar. The word used for ‘plates' regularly means ‘snares'. Whenever men looked on them in future they would remember what had happened to the men who had been ensnared by evil and had tried to supplant the Aaronic priesthood. They would be a ‘sign' to the children of Israel of the legitimacy of that priesthood.
This is not an explanation of how the altar first received a brazen covering. It could never have operated without one. But we are not told how far Bezalel had overlaid it with bronze (Exodus 38:2). These were now additional, attached to the outside of the altar so that they could be a memorial of what had happened.
‘And Eleazar the priest took the brazen censers, which those who were burnt had offered, and they beat them out for a covering of the altar, to be a memorial to the children of Israel, to the end that no stranger, who is not of the seed of Aaron, come near to burn incense before Yahweh, that he be not as Korah, and as his company, as Yahweh spoke to him by Moses.'
Then Eleazar did as Yahweh commanded. He took the brazen censers which had been offered to Yahweh by those who had been consumed with fire, and ‘they' (the priests or possibly the Levites) beat them for a covering for the altar. They were to be a memorial to the children of Israel, a warning, that no stranger, that is, no non-Aaronide, should come near to burn incense before Yahweh. For were they to do so they would end up like Korah and his band of Levites as Yahweh had spoken to Moses.
Here then we have the import to which the whole account has built up, that the sanctuary was the exclusive province of the sons of Aaron.
The whole account is a warning against rebelling against Yahweh's true servants, and against using false methods in order to approach God. For now there is only one way of access, through our great High Priest, the Lord Jesus Christ, and we can approach in no other way.