Bible Study: Beware of false teachers

The apostle Jude warns the believers to remain in the correct, apostolic faith and not be misled by heresies and false teachers who will only lead a person to spiritual death.  How can we remain there as well but also live out our faith instead of existing in a duality, i.e. I act one way in church and different at home or in public. How can Christ remain within me and live in me always?