2nd John 1:8

5 And now I beseech thee, lady, not as though I wrote to thee a new commandment, but that which we had from the beginning, that we love one another.

6 And this is love, that we should walk after his commandments. This is the commandment, even as ye heard from the beginning, that ye should walk in it.

7 For many deceivers are gone forth into the world, [even] they that confess not that Jesus Christ cometh in the flesh. This is the deceiver and the antichrist.

8 Look to yourselves, that ye lose not the things which we have wrought, but that ye receive a full reward.

9 Whosoever goeth onward and abideth not in the teaching of Christ, hath not God: he that abideth in the teaching, the same hath both the Father and the Son.

10 If any one cometh unto you, and bringeth not this teaching, receive him not into [your] house, and give him no greeting:

11 for he that giveth him greeting partaketh in his evil works.