2 Peter 2:20-22

20For if after they have escaped the filthy things of the world through the rich knowledge of our Lord and Savior Jesus Christ, they again get entangled in them and succumb to them, their last state has become worse for them than their first.

21For it would have been better for them never to have known the way of righteousness than, having known it, to turn back from the holy commandment that had been delivered to them.

22They are illustrations of this true proverb: “A dog returns to its own vomit,” and “A sow, after washing herself, wallows in the mire.”