Whether private persons are bound by a pledge given to the enemy

It is strange that legal authorities have been found who would teach that the obligation was binding when an agreement was made publicly with the enemy, but that agreements made by private persons were not binding in like manner. For since private citizens have private rights, which they can place under obligation, and enemies are capable of acquiring right, what can stand in the way of the obligation? Add that, unless this rule is established, opportunity is given for slaughter [of captives], an impediment is set to liberty. For captives in many cases will not be able to guard against the former, or to obtain the latter, if the good faith of private persons has been done away with.

Whether private persons are bound even to a pirate or brigand

Still further, not only is a pledge, which has been given to an enemy, recognised by the law of nations, but also a pledge to a brigand or to a pirate, just as we have said above in regard to public faith. There is this difference, that if an unjust fear inspired by the other has induced the promise, the promisor can demand restitution; or if the other party is unwilling to make restitution, he can take it [by force]; such a procedure [however] has no place in case of a fear arising from a public war, according to the law of nations.