Dishonest scales are an abomination to the Lord, but a just weight is His delight. (Proverbs 11:1)
How you transact business says something about your integrity. The dishonest person uses a heavy weight to measure his purchases (so he gets more product than he deserves), and he sells using a lighter weight (so he makes more profit than is rightfully his). Be honest in all your transactions. For example, do not accept too much change back when making a purchase (it is money that doesn’t belong to you). Pay the full amount agreed upon when making a purchase (to do otherwise is stealing). God knows whether you are honest when you buy and sell. He is pleased when He sees your honesty in every transaction you make.