 129 steadfastness which is the validity of the contract and steadfastness which is obstinacy are two confused things that can only be distinguished by someone who knows the nature of morals. the difference between them is that obstinacy is what is based on falsehood or what the doer did in support of what he was involved in and its corruption became apparent to him or its correctness or corruption did not become apparent to him. this is reprehensible and its opposite is fairness. as for steadfastness which is the validity of the contract it is only based on the truth or on what a person believes to be true as long as its falsehood does not become apparent to him. this is praiseworthy and its opposite is confusion. some of these two are only to be blamed because they neglected to manage what they were steadfast on and left the investigation into whether what they committed to was true or false.
١٢٩ الثبات الذي هو صحة العقد، والثبات الذي هو اللجاج مشتبهان اشتباها لا يفرق بينهما إلا عارف بكيفية الأخلاق. والفرق بينهما أن اللجاج هو ما كان على الباطل أو ما فعله الفاعل نصرا لما نشب فيه، وقد لاح له فساده او لم يلح له صوابه ولا فساده. وهذا مذموم، وضده الانصاف. وأما الثبات الذي هو صحة العقد فإنما يكون على الحق أو على ما اعتقده المرء حقا ما لم يلح له باطله. وهذا محمود، وضده الاضطراب، وإنما يلام بعض هذين لأنه ضيع تدبير ما ثبت عليه وترك البحث عما التزم أحق هو أم باطل.