It is not false doctrine abstractedly, neither is it a person, but evil spirits are at work, and this discernment of spirits is in question in 1 John 1-3.
Verses 3 and 4. How gracious of God to permit the evil then to be manifested, that we might have the light and truth needed to meet it in our day. Greater is He THAT is in us, than he that is in the world.