וַיִּשְׁלַ֣ח מֹשֶׁ֔ה לִקְרֹ֛א לְדָתָ֥ן וְלַאֲבִירָ֖ם בְּנֵ֣י אֱלִיאָ֑ב וַיֹּאמְר֖וּ לֹ֥א נַעֲלֶֽה׃
Moïse envoya quérir Dathan et Abirâm, fils d’Elïab; mais ils dirent: "Nous n’irons point.
Rabbeinu Bahya
Looking at the plain meaning of the text I believe that this verse reveals two separate sins these sons of Aaron were guilty of. One sin was of an intellectual nature, i.e. their thinking, their attitude. Death was decreed for them for that sin. This is the meaning of Tanchuma Acharey 6 that the verse in Exodus 24,11 that “G’d did not stretch out His hand against the nobles of Israel who gazed at G’d and ate and drank,” meant that their punishment was placed in abeyance at that time. The words make it plain that these men were already guilty of death at that time. They were temporarily saved as G’d did not want to spoil the joy of the revelation, the giving of the Torah, at that time. This is all derived by inference because in this instance the Torah speaks of בקרבתם instead of בהקריבם. The latter word means: “when they performed an act of offering, etc.” The former word means: “when they came close,” i.e. intellectually. The sin consisting of a deed was the offering of external fire which was not authorised for them to do, (Leviticus 10,1). They offered the fire without offering incense at the same time, seeing mention of their placing incense on their censers appears to refer to a separate action. We may therefore understand the verse in front of us as meaning: “after the death of the two sons of Aaron who had died seeing that G’d had decreed death for them because they were guilty of a sin involving thought when they had come too close before the Lord during the revelation at Mount Sinai feasting their eyes on a vision of G’d.” They died only on the first day of Nissan following (almost 10 months later) because of the additional sin in deed when they introduced external fire as an offering.
When G’d spoke to Moses here He used both the form of address known as אמירה, and that known as דבור. Verse 1 mentions the latter, verse 2 the former kind of address. He was to tell Aaron (אמירה, in a friendly manner) that he and other priests must not enter the part of the Sanctuary which is beyond the dividing curtain except armed with incense. This is elaborated on in verses 12-13 where the Torah describes the cloud of incense covering the lid of the Holy Ark as insurance against Aaron (or whichever High Priest) dying during this procedure. If Aaron were to enter the Holy of Holies without the incense he would die just as his sons had died.
When G’d spoke to Moses here He used both the form of address known as אמירה, and that known as דבור. Verse 1 mentions the latter, verse 2 the former kind of address. He was to tell Aaron (אמירה, in a friendly manner) that he and other priests must not enter the part of the Sanctuary which is beyond the dividing curtain except armed with incense. This is elaborated on in verses 12-13 where the Torah describes the cloud of incense covering the lid of the Holy Ark as insurance against Aaron (or whichever High Priest) dying during this procedure. If Aaron were to enter the Holy of Holies without the incense he would die just as his sons had died.
Ibn Ezra
Controversial matters is the inclusive category. I have already explained the terms you must get up, and ascend [commentary on Numbers 16: 12].
Or HaChaim
The best proof for our theory is the fact that Moses is described as trying to placate only Datan and Aviram when he sent messengers to call them for a chat (Numbers 16,12). When they refused to come, Moses even went to look them up (16,25). The reason was that Moses felt that these two were at the bottom of the whole rebellion. Once we accept this, the death of all the people who perished can be attributed to Datan and Aviram. This results in our being able to find some excuse for both Korach and the 250 men who offered the incense. You find that the Torah wrote in Deut.11,6: "and what He has done to Datan and Aviram, the sons of Eliav, how the earth opened its mouth and swallowed them, their houses, and their tents and every living thing which followed them." Moses attributed the entire debacle exclusively to Datan and Aviram. Having explained this, we can now understand the scholar in Sanhedrin 110 who holds that the company of Korach does not qualify for life in the hereafter as referring only to Datan and Aviram. The contrary opinion who holds that Korach and company will enjoy life in the hereafter and who base themselves on Samuel I 2,8 that "G'd lowers people to Sheol and brings them up again," must be understood as referring to Korach and companions exclusive of Datan and Aviram to whom the verse does not apply.