Quest. XII. May I not make advantage of another's ignorance or error in bargaining?
Answ. Not to get more than your commodity is worth, nor to get his goods for less than the worth; no, nor to get the true worth against his will, or with scandal: but if it be only to get a true worth of your own commodity when he is willing, but would be offended if his ignorance in some point were cured, you may so far make use of his ignorance to a lawful end, as is said before in the case of concealing faults.
Quest. XIII. May I strive to get before another, to get a good bargain which he desireth?
Answ. Yes, if you do it not out of a greedy mind, nor to the injury of one that is poorer than yourself: you should rather further the supply of your neighbour's greater needs; otherwise speed and industry in your calling is no fault, nor yet the crossing of a covetous man's desires: you are not bound to let every man have what he would have.
Quest. XIV. May I buy a thing out of another's hand, or hire a servant which another is about or is treating with? Or may I call a chapman from another to buy of me?
Answ. There are some cases in which you may not do it, and some in which you may. You may not do it out of a greedy covetousness; nor to the injury of the poor: nor when the other hath gone so far in the bargain that it cannot be honestly broken; for then you injure the third person, and tempt the other to a sin: nor may you do it so as to disturb the due and civil order, which should be among moderate men in trading. And it is a great matter how the thing is accounted of by the custom of the country or market where you bargain; for where it is of ill report, and accounted as unjust, the scandal should make you avoid such a course. But yet in some cases it is lawful, and in some a needful duty. It is lawful when none of the foresaid reasons (or any such other) are against it: it is a duty when charity to the poor or oppressed doth require it. As e. g. a poor man must needs sell his land, his horse, his corn, or goods: a covetous oppressor offereth him less than it is worth. The poor man must take his offer if he can get no more: the oppressor saith that it is injustice for any one to take his bargain out of his hand, or offer money till he have done: in this case it may be a duty, to offer the poor man the worth of his commodity, and save him from the oppressor. A covetous man offereth a servant or labourer less than their service or labour is worth; and will accuse you, if you interrupt his bargain and would offer his servant more: in this case it may be your duty to help the servant to a better master. A chapman is ready to be cheated by an unconscionable tradesman, to give much more for a commodity than its worth: charity may oblige you in such a case to offer it him cheaper. In a word, if you do it for your own gain, in a greedy manner, it is a sin; but if you do it when it is not scandalous or injurious, or do it in charity for another's good, it is lawful, and sometimes a duty.
Quest. XV. May I dispraise another's commodity to draw the buyer to my own?
Answ. This case is sufficiently answered in the former: 1. You may not use any false dispraise: 2. Nor a true one out of covetousness, nor in a scandalous manner. 3. But you may help to save another from a cheater, by opening the deceit in charity to him.
Quest. XVI. What should I do in doubtful cases, where I am uncertain whether the thing be just or not?
Answ. Causeless, perplexing, melancholy scruples, which would stop a man in the course of his duty, are not to be indulged: but in rational doubts, first use your utmost diligence (as much as the nature of the cause requireth) to be resolved; and if yet you doubt, be sure to go the safer way, and to avoid sin rather than loss, and to keep your consciences in peace.