Offering the wheat for sale is to advertise a product for a certain weight (e.g. 2 kg) and then to give less than that weight to the customer (e.g. 1.5 kg). Making the ephah small and the shekel great would be to sell essential goods such as bread at an inflated price.
Rigging the scales was forbidden in Law (Leviticus 19:35–36; Deuteronomy 25:13–15), attacked by the prophets (Micah 6:10; Ezekiel 45:9–12), and condemned in the wisdom writings (Proverbs 11:1; Proverbs 16:11; Proverbs 20:23; Job 31:6). By using weights scaled in the merchants’ favour, people were cheated into giving more money for less grain.
5 saying, “When will the new moon be over, that we may sell grain? And the Sabbath, that we may offer wheat for sale, that we may make the ephah small and the shekel great and deal deceitfully with false balances,