Though Paul deals a lot with false teachers in the letters to Timothy and Titus, he is not the only New Testament writer to deal with the subject. Peter has a lot to say about these deceivers, as well as those who are deceived by them.
Much of Peter’s second letter is devoted to encouraging Christians to grow in Jesus and beware of false teachers. To beware of false teachers, we must be able to tell the difference between true and false doctrine. One way we do that is by understanding the source of each one.
A focus of 2 Peter is the danger of false teachers, and in Chapter 2 he begins to discuss the source of their doctrine, the perversion of the truth. But before that, at the end of chapter 1 he gives us some insight into the source of true doctrine.