2 Peter 2:22

Their case is that described in the true proverb, "A dog returns to what he has vomited," and also in the other proverb, "The sow has washed itself and now goes back to roll in its filth."

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
The heavy rain descends, the swollen torrents come, and the winds blow and burst upon the house, and it falls; and disastrous is the fall."
Luke 14:30
saying, 'This man began to build, but could not finish.'
Luke 17:32
Remember Lot's wife.
1 Timothy 5:15
For already some of them have gone astray, following Satan.