1, § 10, the term means the binding and coercive force which constrains every man to perform the agre& ments. he has made; RY forge grounded ‘jn: the ethical principle of fidelity to one’s promises, buc deriving its legal efficacy from {ts retogn tio by positive law, and sanctioned ‘by ‘the’ pro viding a remedy for the infraction of the: duty