Heidelberg Catechism – Lord’s Day 42
Q. What does God forbid in the eighth commandment?
A. He forbids not only the theft and robbery which civil authorities punish, but God also labels as theft all wicked tricks and schemes by which we seek to get for ourselves our neighbor’s goods, whether by force or under the pretext of right, such as false weights and measures, deceptive advertising or merchandising, counterfeit money, exorbitant interest, or any other means forbidden by God. He also forbids all greed and misuse and waste of his gifts.
Q. But what does God require of you in this commandment?
A. That I work for the good of my neighbor wherever I can and may, deal with him as I would have others deal with me, and do my work well so that I may be able to help the poor in their need.