Deuteronomy 25:13-16

You shall not keep two different weights in your bag, one large and the other small; nor shall you keep two different measures in your house, one large and the other small.  But use a true and just weight, and a true and just measure, that you may have a long life on the land which the LORD, your God, is giving you.  Everyone who is dishonest in any of these matters is an abomination to the LORD, your God.