Do not buy a pig in a poke.

A buyer cannot judge an animal’s condition or value while it remains hidden. The proverb warns against making a purchase without seeing what is being offered.

More broadly, it advises checking important details before accepting a deal or making a commitment, rather than relying on assurances alone.

Use it to urge someone to inspect an item or check the terms of an offer before paying or agreeing, particularly when a decision would otherwise rest on unseen details.