There were false prophets among the people, even as there shall be false teachers among you: which privily shall bring in damnable sects, even denying the Lord that hath bought them, and bring upon themselves swift damnation.

After

"Moreover, if thy brother trespass against thee, Go and tell him his fault between him and thee alone. If he hear thee, thou hast won thy brother:

I told you before, and tell you before, and as I said when I was present with you the second time, so write I now, being absent, to them which in time past have sinned, and to all others: that if I come again, I will not spare;

Reject

I beseech you, brethren: mark them which cause division, and give occasions of evil contrary to the doctrine which ye have learned; and avoid them.

in the name of our Lord Jesus Christ, when ye are gathered together, and my spirit, with the power of the Lord Jesus Christ,

I would to God they were separated from you, which trouble you.

We require you, brethren, in the name of our Lord Jesus Christ, that ye withdraw yourselves from every brother that walketh inordinately, and not after the institution which ye received of us.

having a similitude of godly living, but have denied the power thereof. Such abhor.

If there come any unto you and bring not this learning, him receive not to house: neither bid him Godspeed.