What does God forbid in the eighth commandment?
God forbids not only those thefts and robberies which the authorities punish, but He includes under the name of theft all wicked tricks and devices by which we design to appropriate to ourselves the goods which belong to our neighbour, whether it be by force or under a pretence of right, as by unjust weights, lengths, measures, fraudulent merchandise, false coins, exploitative lending, or by any other way forbidden by God; as also all greed, all abuse and waste of His gifts.
But what does God require in this commandment?
That I promote the advantage of my neighbour in every instance I can or may, and deal with him as I desire to be dealt with by others; further also that I faithfully labour so that I may be able to relieve the needy.