One of the marks of a disciple of Jesus will be that they abide in orthodox doctrine.
2 John 7 For many deceivers have gone out into the world, those who do not confess the coming of Jesus Christ in the flesh. Such a one is the deceiver and the antichrist. 8 Watch yourselves, so that you may not lose what we have worked for, but may win a full reward. 9 Everyone who goes on ahead and does not abide in the teaching of Christ, does not have God. Whoever abides in the teaching has both the Father and the Son.