In the principal act itself, the proper equality requires that no more should be demanded either party than what is just. Which can scarce have a place in gratuitous acts. To stipulate for a recompence in return for a loan, or for the service of labour or commission is doing no wrong, but constitutes a kind of mixed contract, partaking of the nature of a gratuitous act, and an act of exchange. And in all acts of exchange, this equality is to be punctually observed. Nor can it be said that if one party promises more, it is to be looked upon as a gift. For men never enter into contracts with such intentions, nor ought the existence of such intentions ever be presumed, unless they evidently appear. For all promises or gifts, in these cases, are made with an expectation of receiving an equivalent in return. "When, _in the words of Chrysostom_, in all bargains and contracts, we are anxious to receive MORE and give LESS than is due, what is this but a species of fraud or robbery?" The writer of the life of Isidorus in Photius, relates of Hermias, that when any thing, which he wished to purchase was valued at too low a rate, he made up the deficiency of the price, thinking that to act otherwise was a species of injustice, though it might escape the observation of others. And in this sense, may be interpreted the law of the Hebrews. XII. There remains another degree of equality to be considered, arising out of the following case. It may happen in contracts that although nothing is concealed, which ought to be made known, nor more exacted or taken by one party than is due, yet there may be some inequality without any fault in either of the parties. Perhaps, for instance there might be some unknown defect in the thing, or there might be some mistake in the price. Yet, in such cases, to preserve that equality, which is an essential requisite in all contracts, the party suffering by such defect or mistake, ought to be indemnified by the other. For in all engagements it either is, or ought to be a standing rule, that both parties should have equal and just advantages. It was not in every kind of equality that the Roman law established this rule, passing over slight occasions, in order to discourage frequent and frivolous litigation. It only interposed its judicial authority in weighty matters, where the price exceeded the just value by one half. Laws indeed, as Cicero has said, have power to compel, or restrain men, whereas philosophers can only appeal to their reason or understanding. Yet those, who are not subject to the power of civil laws ought to comply with whatever reason points out to them to be just: So too ought they, who are subject to the power of human laws, to perform whatever natural and divine justice requires, even in cases, where the laws neither give nor take away the right, but only forbear to enforce it for particular reasons.