2 John 4-11 New Revised Standard Version (NRSV)
Truth and Love
4 I was overjoyed to find some of your children walking in the truth, just as we have been commanded by the Father. 5 But now, dear lady, I ask you, not as though I were writing you a new commandment, but one we have had from the beginning, let us love one another. 6 And this is love, that we walk according to his commandments; this is the commandment just as you have heard it from the beginning—you must walk in it.
7 Many deceivers have gone out into the world, those who do not confess that Jesus Christ has come in the flesh; any such person is the deceiver and the antichrist! 8 Be on your guard, so that you do not lose what we[a] have worked for, but may receive a full reward. 9 Everyone who does not abide in the teaching of Christ, but goes beyond it, does not have God; whoever abides in the teaching has both the Father and the Son. 10 Do not receive into the house or welcome anyone who comes to you and does not bring this teaching; 11 for to welcome is to participate in the evil deeds of such a person.