THIS MIGHT SURPRISE YOU
The answer
It's an English proverb — Sir Thomas Browne put it in print in 1642. People sometimes anchor it to 1 Timothy 5:8 ("whoever does not provide for their relatives..."), but that verse never says it.
Why it’s interesting
This is how a proverb gets "biblical": someone finds a verse in the neighborhood and the two fuse. The saying and the verse point in similar directions, which is exactly what makes the swap invisible.
Scholarly consensus
You can know the Bible.
Not just the stories, but the history, authorship, and scholarship behind it.