2 John 1:8-13 RSV

8 Look to yourselves, that you may not lose what you have worked for, but may win a full reward.
9 Any one who goes ahead and does not abide in the doctrine of Christ does not have God; he who abides in the doctrine has both the Father and the Son.
10 If any one comes to you and does not bring this doctrine, do not receive him into the house or give him any greeting;
11 for he who greets him shares his wicked work.
12 Though I have much to write to you, I would rather not use paper and ink, but I hope to come to see you and talk with you face to face, so that our joy may be complete.
13 The children of your elect sister greet you.