2 Peter 2:20-22

They were made free from the evil in the world by knowing our Lord and Savior Jesus Christ. But if they return to evil things and those things control them, then it is worse for them than it was before. Yes, it would be better for them to have never known the right way than to know it and to turn away from the holy teaching that was given to them. What they did is like this true saying: “A dog goes back to what it has thrown up,” and, “After a pig is washed, it goes back and rolls in the mud.”