Peter says in verse 18, “For they mouth empty, boastful words and, by appealing to the lustful desires of sinful human nature, they entice people who are just escaping from those who live in error.” This is why these false teachers are so terribly dangerous. They speak well as if they are absolutely confident in what they are saying. And when the faith is weak, and the sinful nature is strong, then seducing them to falsehood or to false teaching is not so hard any more. Most people like to hear that they can follow Christ, and at the same time enjoy the desires of their sinful nature. It is not hard to understand why those who are not grounded in the gospel faith can be easily deceived.