idle hands are the devil's workshop
- idle hands are the devil's playthings
- idle hands are the devil's tools
- the devil makes work for idle hands
- the devil finds work for idle hands
- any of these, but with Devil in place of devil
This proverb is thought by some to originate from the Bible, the book of Proverbs chapter 16 verse 27 (Proverbs 16:27). Yet this is probably a misreading driven by an application of Protestant theological assumptions. The King James version of the verse refers only to ungodliness: An ungodly man diggeth up evil: and in his lips there is as a burning fire.
Only The Living Bible of 1971 injects the idea of idleness into its translation: Idle hands are the devil’s workshop; idle lips are his mouthpiece. (TLB also adds the literal translation: A worthless man devises mischief; and in his lips there is a scorching fire.)
Proverbs 16:27 may have inspired St. Jerome to write in the late 4th century: fac et aliquid operis, ut semper te diabolus inveniat occupatum, or “engage in some occupation, so that the devil may always find you busy.” This was later repeated by Chaucer in the Canterbury Tales, which was probably the source of its popularity.