DID YOU KNOW?
The answer
Not in the Bible. John Wesley used it in a 1791 sermon, and he quoted it as an already-old saying rather than scripture.
Why it’s interesting
The idea has ancient roots in ritual-purity traditions, but the tidy English proverb is Wesley's era, not the Bible's. It's a good example of a sermon phrase graduating into "something the Bible says."
Scholarly consensus
You can know the Bible.
Not just the stories, but the history, authorship, and scholarship behind it.