Jude 1:11
Woe unto them! for they have gone in the way of Cain, and ran greedily after the error of Balaam for reward, and perished in the gainsaying of Core.

In Hebrew Core is Korah
Numbers 16:1
  Jude 1:8-16 False teachers are dreamers; they greatly defile and grievously wound the soul. These teachers are of a disturbed mind and a seditious spirit; forgetting that the powers that be, are ordained of God, Ro 13:1.
   As to the contest about the body of Moses, it appears that Satan wished to make the place of his burial known to the Israelites, in order to tempt them to worship him, but he was prevented, and vented his rage in desperate blasphemy.
 This should remind all who dispute never to bring railing charges. Also learn hence, that we ought to defend those whom God owns. It is hard, if not impossible, to find any enemies to the TRUE Christian religion, who did not, and do not, live in open or secret contradiction to the principles of natural religion. Such are here compared to brute beasts, though they often boast of themselves as the wisest of mankind.
 They corrupt themselves in the things most open and plain. The fault lies, not in their understandings, but in their depraved wills, and their disordered appetites and affections. It is a great reproach, though unjust to religion, when those who profess it are opposed to it in heart and life.

  God will remedy this in his time and way; not in men's blind way of plucking up the wheat with the tares. It is sad when men begin in the Spirit, and end in the flesh. Twice dead; they had been once dead in their natural, fallen state; but now they are dead again by the evident proofs of their hypocrisy.
 Dead trees, why cumber they the ground! Away with them to the fire. Raging waves are a terror to sailing passengers; but when they get into port, the noise and terror are ended.

 False teachers are to expect the worst punishments in this world and in that to come. They glare like meteors, or falling stars, and then sink into the blackness of darkness for ever

 Many now do not at all refer to the terms godly, or ungodly, unless it be to mock at even the words; but it is not so in the language taught us by the Holy Ghost. Hard speeches of one another, especially if ill-grounded, will certainly come into account at the day of judgment. These evil men and seducers are angry at every thing that happens, and never pleased with their own state and condition. Their will and their fancy, are their only rule and law. Those who please their sinful appetites, are most prone to yield to ungovernable passions.

 The men of God, from the beginning of the world, have declared the doom denounced on them. Such let us avoid. We are to follow men only as they follow God's anointing


From Bible Hub

Korah's parable

The Death of Korah, Dathan, and Abiram, by Gustave Doré. Korah incited all the people against Moses, arguing that it was impossible to endure the laws instituted by the latter.

He told them the following parable: "A widow, the mother of two young daughters, had a field. When she came to plow it, Moses told her not to plow it with an ox and an ass together (Deut. xxii. 10); when she came to sow it, Moses told her not to sow it with mingled seeds (Lev. xix. 19).

At the time of harvest she had to leave unreaped the parts of the field prescribed by the Law, while from the harvested grain she had to give the priest the share due to him. The woman sold the field and with the proceeds bought two sheep.

But the first-born of these she was obliged to give to Aaron the priest; and at the time of shearing he required the first of the fleece also (Deut. xviii. 4). The widow said: 'I can not bear this man's demands any longer. It will be better for me to slaughter the sheep and eat them.' But Aaron came for the shoulder, the two cheeks, and the maw (ib. verse 3).

The widow then vehemently cried out: 'If thou persistest in thy demand, I declare them devoted to the Lord.' Aaron replied: 'In that case the whole belongs to me' (Num. xviii. 14), whereupon he took away the meat, leaving the widow and her two daughters wholly unprovided for" (Num. R. xviii. 2-3; Tan., Ḳoraḥ, 4-6).

The question how it was possible for a wise man like Korah to be so imprudent as to rebel is explained by the fact that he was deceived through his own prophetical capacity. He had foreseen that the prophet Samuel would be his descendant, and therefore concluded that he himself would escape punishment. But he was mistaken; for, while his sons escaped, he perished (Num. R. xviii. 7; Tan., Ḳoraḥ, 12).

Destruction of Korah

At the time of Korah's engulfment, the earth became like a funnel, and everything that belonged to him, even linen that was at the launderer's and needles that had been borrowed by persons living at a distance from Korah, rolled till it fell into the chasm (Yer. Sanh. x. 1; Num. R. l.c.).

According to the Rabbis, Korah himself underwent the double punishment of being burned and buried alive (Num. R. l.c. 14; Tan., Ḳoraḥ, 23).

He and his followers continued to sink till Hannah prayed for them (Gen. R. xcviii. 3); and through her prayer, the Rabbis declare, Korah will ascend to paradise (Ab. R. N. xxxvi.; Num. R. xviii. 11; comp. Sanh. 109b).

Rabbah bar bar Ḥana narrates that while he was traveling in the desert, an Arab showed him the place of Korah's engulfment. There was at the spot a slit in the ground into which he introduced some wool soaked in water. The wool became parched.

On placing his ear to the slit, he heard voices cry: "Moses and his Torah are true; and we are liars" (B. B. 74a; comp. Tan., ed. Buber, Ḳoraḥ, Supplement).S. S. M. Sel.

The Biblical name Korah is important because it became associated with Biblical villains and traitors for two reasons: In the case of Korah son of Esau, both Esau and Korah waged war against Israel, and Esau was hated by God because of it according to Malachi 1:3. In these struggles, Korah became renowned as a warrior and a fighter, and was legendary in Canaan because of abilities. In the case of Korah son of Izhar, he is remembered for the rebellious action together with Dathan and Abiram against Moses according to Numbers 16:21. This story also appears in the Qur'an, where Korah is named Qarun (see Biblical narratives and the Qur'an). The story of this "fallen Levite" or "corrupted priest" is one of the many stories in the Scriptures that, in sharp contrast to most ancient literature, allows criticism of an honorable office, similarly to the criticism of King David's infidelity.

From Wikipedia Under Korah