Deuteronomy 25:13-16 - Honest Weights And Measures
13 "You shall not have in your bag two kinds of weights, a large and a small. 14 You shall not have in your house two kinds of measures, a large and a small. 15 A full and fair weight you shall have, a full and fair measure you shall have, that your days may be long in the land that the LORD your God is giving you. 16 For all who do such things, all who act dishonestly, are an abomination to the LORD your God.