Only the person's own word stands as a constraint, but that word is itself an instance of the same promise-keeping obligation that was already in question.

’Tis ridiculous to say, there is any Obligation on Man to act sociably, or honestly, in a form’d Government; and not in that which is commonly call’d the State of Nature. For, to speak in the fashionable Language of our modern Philosophy: “Society being founded on a Compact; the Surrender made of every Man’s private unlimited Right, into the hands of the Majority, or such as the Majority shou’d appoint, was of free Choice, and by a Promise.” Now the Promise it-self was made in the State of Natur