Cross reference
Proverbs 26:11
11 As a dog returneth to his vomit, so a fool returneth to his folly.
Exodus 8:15
15 But when Pharaoh saw that there was respite, he hardened his heart, and hearkened not unto them; as the LORD had said.
2 Peter 2:22
22 But it is happened unto them according to the true proverb, The dog is turned to his own vomit again; and the sow that was washed to her wallowing in the mire.
Matthew 12:45
45 Then goeth he, and taketh with himself seven other spirits more wicked than himself, and they enter in and dwell there: and the last state of that man is worse than the first. Even so shall it be also unto this wicked generation.