2 Peter 2:22

What has happened to them shows the truth of the proverb, "A dog returns to what he has vomited up, and a sow that has washed goes back to wallow in the mire."

Treasury of Scripture Knowledge

Summary

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.

Bible References

General references

Matthew 7:27
And the rain fell, and the rivers rose, and the winds blew and beat about that house, and it went down, and its downfall was complete."
Luke 14:30
and say, 'This man started to erect a building, and could not finish it!'
Luke 17:32
Remember Lot's wife!
1 Timothy 5:15
For some widows have already turned aside to follow Satan.