2 Peter 2:20-22

And when people escape from the wickedness of the world by knowing our Lord and Savior Jesus Christ and then get tangled up and enslaved by sin again, they are worse off than before. It would be better if they had never known the way to righteousness than to know it and then reject the command they were given to live a holy life. They prove the truth of this proverb: “A dog returns to its vomit.” And another says, “A washed pig returns to the mud.”