Jude 1:11

“I and my colleagues who were present with me were deeply and grievously distressed, dearest brother, on reading your letter in which you complained of your deacon, that, forgetful of your priestly station, and unmindful of his own office and ministry, he had provoked you by his insults and injuries. And you indeed have acted worthily, and with your accustomed humility towards us, in rather complaining of him to us; although you have power, according to the vigour of the episcopate and the authority of your See, whereby you might be justified on him at once, assured that all we your colleagues would regard it as a matter of satisfaction, whatever you should do by your priestly power in respect of an insolent deacon, as you have in respect of men of this kind divine commands. Inasmuch as the Lord God says in Deuteronomy, "And the man that will do presumptuously, and will not hearken unto the priest or the judge, whoever he shall be in those days, that man shall die; and all the people, when they hear, shall fear, and shall no more do impiously." And that we may know that this voice of God came forth with His true and highest majesty to honour and avenge His priests; when three of the ministers -Korah, Dathan, and Abiram-dared to deal proudly, and to exalt their neck against Aaron the priest, and to equal themselves with the priest set over them; they were swallowed up and devoured by the opening of the earth, and so immediately suffered the penalty of their sacrilegious audacity. Nor they alone, but also two hundred and fifty others, who were their companions in boldness, were consumed by a fire breaking forth from the Lord, that it might be proved that God's priests are avenged by Him who makes priests. In the book of Kings also, when Samuel the priest was despised by the Jewish people on account of his age, as you are now, the Lord in wrath exclaimed, and said, "They have not rejected thee, but they have rejected me." And that He might avenge this, He set over them Saul as a king, who afflicted them with grievous injuries, and trod on the people, and pressed down their pride with all insults and penalties, that the despised priest might he avenged by divine vengeance on a proud people.”

“These people are even fratricides, because what they teach kills the souls of those who are deceived by them. Look how he describes their outrageous ungodliness. He is not content to compare them with Cain but adds Ba-laam and Korah as well. Cain we understand from the above. Balaam he adds because Ba-laam went out to curse God's people for the sake of money, even if God later turned his tongue around to the point where he blessed them instead. Korah is mentioned because he seized a teaching authority which God had not granted to him.”

“Woe to them who have gone in the way of Cain, etc. They go in the way of Cain, who assume for themselves the name of learned men out of envy for their betters to be honored. And they pour themselves out in the error of Balaam, who for the love of earthly goods, attack the truth which they themselves know. They perish in the contradiction of Korah, who descended alive into the inferno, whoever separates themselves from the unity of the Holy Church with the desire of undue primacy, knowing and foreseeing how much evil they carry, yet they descend to the abyss of crimes. And indeed the Lord reproached Cain for thinking of fratricide, but envy did not let him be saved. Balaam, however, desiring to walk against the people of God, the Lord forbade, but the love of money hindered him from obeying. Moses tried to calm Korah, who was boasting, speaking for the Lord; but his pride made him incurable. Thus indeed, thus do heretics act, who, scorned by the rebuke of the holy Church, refuse to be corrected; rather they strive to kill their brothers with the sword of evil doctrine, as Cain did, deceive them with evil counsel as Balaam did, and rise up against catholic teachers as Korah did, to their own destruction.”

“Woe to them, because they went in the way of "Cain" through fratricide; for, teaching impious doctrine to brethren, that is, to fellow men, they kill them with their evil teachings, or: by devouring the seed, they kill their brethren in potentiality, that is, those whom the seed, brought to maturity, would have brought into life. They went in the way of "Balaam," because they too do what they do for the sake of gain, like Balaam. They went in the way of "Korah," because, like him, being unworthy, they seized for themselves the dignity of the teaching office.”

“Woe to them, for they have gone the way of Cain, and for profit they have abandoned themselves to the error of Balaam, and in the contradiction of Korah they perished. "The way of Cain": this is, through the murder of a brother: for those teaching such things also kill their brothers, or men of the same sort, with wicked doctrines. Or even by absorbing the seed, they kill the brother in virtue, whom the fruitfulness of the seed would bring forth to life. "the error of Balaam", because they, like him, do these things for the sake of gain. Furthermore, the way of Korah, because they, like him, seized the office of teacher, being unworthy.”