I have promised a benefit in case nothing occurs to show that I ought not to give it. For what if my country should bid me give to her what I have promised to another? What if a law should be passed, forbidding anyone to do what I had promised that I would do for my friend? Suppose I have promised you my daughter in marriage, but find out later that you are not a citizen; I have no right to contract a marriage with a foreigner; the same circumstance that forbids it provides my defense. Only then shall I be breaking faith, only then shall I listen to a charge of inconstancy, if I fail to fulfill a promise though all the circumstances remain the same as they were when I made my promise; otherwise, any chance that takes place gives me the liberty of revising my decision, and frees me from my pledge. Suppose I have promised my legal assistance, but afterwards discover that a precedent was being sought from that case to harm my father; suppose I have promised that I will go abroad, but word is brought that the way is beset with robbers; suppose I was about to go to keep an appointment, but am detained by the illness of my son or by my wife’s confinement. If you are to hold me to the fulfillment of my promise all the circumstances must remain the same as they were when I promised; but what greater change can there be than my discovery that you are a bad and ungrateful man? I shall refuse to an unworthy man what I was willing to give to him supposing him to be worthy, and I shall even have reason to be angry because I was deceived.