Be bail and pay for it.

If you agree to guarantee another person’s obligation, you may end up paying what they owe. The proverb treats that financial risk as a reason to think carefully before making the promise.

It also warns against assuming responsibility for someone else’s commitments lightly. An offer meant to help another person can become a cost borne by the person who offered it.

Use it to caution someone who is considering acting as a guarantor, or to comment on a case where doing so has led to payment. The tone is blunt: it emphasizes the possible cost of backing another person’s promise.