2 John 1:9-11
9 Whosoever transgresseth, and abideth not in the doctrine of Christ, hath not God. He that abideth in the doctrine of Christ, he hath both the Father and the Son.
10 If there come any unto you, and bring not this doctrine, receive him not into your house, neither bid him God speed:
11 For he that biddeth him God speed is partaker of his evil deeds.
The Grace New Testament Commentary - 2 John 1:9
1:9 If the church John was addressing was not vigilant as he has just warned them to be, or if one (or more) of its members gave in to the new theology, John states that such a person transgresses (parabainō, "to go aside") and does not abide (menō, "to stay") in the doctrine of Christ. He turns aside from the truth instead of remaining in it.
The person who does not abide in the true doctrine about Jesus Christ does not have God with him in his new perspective and/or lifestyle. He is out of touch with God, while he who abides in the doctrine of Christ is vitally in touch with God.