[3] According to Hans Wehberg, a professor of international law, "few rules for the ordering of Society have such a deep moral and religious influence" as this principle.
The first known expression of the brocard is in the writings of the canonist Cardinal Hostiensis from the 13th century AD, which were published in the 16th.
[7] For example, in the United States—a common law jurisdiction—the implied duty of good faith and fair dealing exists in all commercial contracts.
[8] Under international law, "every treaty in force is binding upon the parties to it and must be performed by them in good faith.
The legal principle of clausula rebus sic stantibus in customary international law also permits non-satisfaction of obligations pursuant to treaty because of a compelling change of circumstances.