DID YOU KNOW?
The answer
The exact rhyme is from Samuel Butler's satirical poem Hudibras (1663). Proverbs 13:24 carries the sentiment — "Those who spare the rod hate their children" — but not the memorable wording.
Why it’s interesting
A 17th-century comic poem gave the idea its stickiest form, and the Bible got the credit. The verse it's mapped onto is real; the slogan is literary.
Scholarly consensus
You can know the Bible.
Not just the stories, but the history, authorship, and scholarship behind it.