Let your prices be according to that measure of good and evil which is established in the fame and common accounts of the wisest and most merciful men, skilled in that manufacture or commodity; and the gain such, which, without scandal, is allowed to persons in all the same circumstances.
In intercourse with others, do not do all which thou mayest lawfully do; but keep something within thy power; and, because there is a latitude of gain in buying and selling, take not thou the utmost penny that is lawful, or which thou thinkest so; for although it be lawful, yet it is not safe; and he who gains all that he can gain lawfully, this year, will possibly be tempted, next year, to gain something unlawfully.
Let no man, for his own poverty, become more oppressing and cruel in his bargain; but quietly, modestly, diligently, and patiently recommend his estate to God, and follow his interest, and leave the success to Him.
Detain not the wages of the hireling; for every degree of detention of it beyond the time, is injustice and uncharitableness, and grinds his face till tears and blood come out; but pay him exactly according to covenant, or according to his needs.
Religiously keep all promises and covenants, though made to your disadvantage, though afterward you perceive you might have done better; and let not any precedent act of yours be altered by any after-accident. Let nothing make you break your promise, unless it be unlawful or impossible; that is, either out of your nature or out of your civil power, yourself being under the power of another; or that it be intolerably inconvenient to yourself, and of no advantage to another; or that you have leave expressed or reasonably presumed.
Let no man take wages or fees for a work that he cannot do, or cannot with probability undertake; or in some sense profitably, and with ease, or with advantage manage. Let no man appropriate to his own use, what God, by a special mercy, or the Republic, hath made common; for that is against both Justice and Charity.
That any man should be the worse for us, and for our direct act, and by our intention, is against the rule of equity, of justice, and of charity. We then do not that to others, which we would have done to ourselves; for we grow richer upon the ruins of their fortune.