2 Peter 2:20-22

For if, after they have escaped the defilements of the world through the knowledge of our Lord and Savior Jesus Christ, they are again entangled in them and overcome, the last state has become worse for them than the first. For it would have been better for them never to have known the way of righteousness than after knowing it to turn back from the holy commandment delivered to them. What the true proverb says has happened to them: “The dog returns to its own vomit, and the sow, after washing herself, returns to wallow in the mire.”