They are... wandering stars, for whom blackest darkness has been reserved forever.
Jude 13
Stars were very important in ancient culture. We have GPS, they had the regular course of the stars. That was how they navigated. Stars that were fixed or regular in their orbits meant everything to them. But, if a person were deceived and tried to navigate by a wandering star (a star that didn’t have a regular orbit), then they could very easily end up lost or even dead.
Jude says that this is what false teachers are like. They claim to be guides, but they only deceive people and lead them astray. Jude says that these false teachers will end up in the blackest darkness just like a shooting star that disappears into the black emptiness of space.
This leads us to a question that every single believer should ask about anyone who would step forward to teach or preach God's Word to them. Here it is: "Does this person adhere to the predictable pattern of sound doctrine or are they a wandering star?" In other words, if you navigate your life based on their teaching, will you arrive at spiritual maturity or be lost to the Christian faith? Where are they leading you?!
You don’t sign up to go on a trip with somebody until you know where they're going. And you shouldn’t let someone teach God’s Word to you until you’re confident that they can lead you back to Jesus over and over again consistently.
Believers today have more choices than ever when it comes to which Bible teachers and preachers they choose to listen to. Whether it's the number of churches in your community, the number of podcasts available on your cellphone, or the number of religious-themed videos and memes you come across on social media; you have more teachers and preachers vying for your attention than ever before. Be very careful who you listen to and who you follow. Make sure you know where they are leading you.