2 Peter 2:20-22

20People can know our Lord and Savior Jesus Christ and escape the world’s filth. But if they get involved in this filth again and give in to it, they are worse off than they were before.

21It would have been better for them never to have known the way of life that God approves of than to know it and turn their backs on the holy life God told them to live.

22These proverbs have come true for them: “A dog goes back to its vomit,” and “A sow that has been washed goes back to roll around in the mud.”