"Now Korah, the son of Izhar, the son of Kohath, the son of Levi, and Dathan and Abiram, the sons of Eliab, and On, the son of Peleth, sons of Reuben, took men: And they rose up before Moses, with certain of the children of Israel, two hundred and fifty princes of the assembly, famous in the congregation, men of renown: And they gathered themselves together against Moses and against Aaron, and said unto them, Ye take too much upon you, seeing all the congregation are holy, every one of them, and the LORD is among them: wherefore then lift ye up yourselves above the congregation of the LORD?" - Numbers 16:1-3
Korah, Datham and Abiram and 250 princes of Israel accuse Moses and Aaron of taking too much upon themselves seeing all the congregation are holy, every one of them, and the LORD is among them.
What these men wanted was to rule over the people of Israel themselves, usurping the God-given authority of Moses and Aaron. In so doing they were rejecting the ordinance of God who established the position of Moses and Aaron and under whose hand He brought the nation of Israel out of slavery in Egypt.
The claim to holiness obviously did not make them holy. The evidence is in verses 26 to 33 (Numbers 16:26-33Numbers 16:26-33 26 And he spake unto the congregation, saying, Depart, I pray you, from the tents of these wicked men, and touch nothing of theirs, lest ye be consumed in all their sins. 27 So they gat up from the tabernacle of Korah, Dathan, and Abiram, on every side: and Dathan and Abiram came out, and stood in the door of their tents, and their wives, and their sons, and their little children. 28 And Moses said, Hereby ye shall know that the LORD hath sent me to do all these works; for I have not done them of mine own mind. 29 If these men die the common death of all men, or if they be visited after the visitation of all men; then the LORD hath not sent me. 30 But if the LORD make a new thing, and the earth open her mouth, and swallow them up, with all that appertain unto them, and they go down quick into the pit; then ye shall understand that these men have provoked the LORD. 31 ¶And it came to pass, as he had made an end of speaking all these words, that the ground clave asunder that was under them: 32 And the earth opened her mouth, and swallowed them up, and their houses, and all the men that appertained unto Korah, and all their goods. 33 They, and all that appertained to them, went down alive into the pit, and the earth closed upon them: and they perished from among the congregation.) of this chapter, where Korah, Dathan and Abiram, and the 250 princes with them, died because of their presumptiveness. They ignored the evidence that God had given the responsibility of the oversight of the children of Israel to Moses and Aaron.The nation were instructed to separate themselves from "these wicked men...lest ye be consumed in all their sins." The nation had to be holy for God to be able to dwell in their midst. Though God dwelt among them, because of the sin of these men, He tested Moses by saying that He would consume the nation (verses 20 and 21). But why would God threaten this if only Korah, Datham, Abiram and the 250 princes were guilty of rebellion? The answer is given in verse 26, and it probably is not the answer that one would at first expect for God says through Moses "Depart, I pray you, from the tents of these wicked men, and touch nothing of theirs, lest ye be consumed in all their sins". The nation were instructed to separate themselves from "these wicked men...lest ye be consumed in all their sins."
Separation from sin and sinners within the ecclesia was, and still is, enjoined upon those who profess to be brethren in Christ.This shows us the true meaning of Holiness, separation from sin, acknowledgement of the authority and supremacy of God and a willingness to obey. It also shows that those who associate themselves with sinners are accepting and condoning the sin and are therefore subject to the same punishment. Separation from sin and sinners within the ecclesia was, and still is, enjoined upon those who profess to be brethren in Christ. The Spirit through Paul (1 Corinthians 5:9, 101 Corinthians 5:9, 10 9 I wrote unto you in an epistle not to company with fornicators: 10 Yet not altogether with the fornicators of this world, or with the covetous, or extortioners, or with idolaters; for then must ye needs go out of the world.) instructs believers "not to company with fornicators: Yet not altogether with the fornicators of this world, or with the covetous, or extortioners, or with idolaters; for then must ye needs go out of the world." We cannot avoid sinners in the world therefore the principle being expounded can only be referring to sinners in the ecclesia.