You shall do no iniquity in justice-in measure, whether in weight or liquid measure. Honest scales, honest weights…you shall have. R. Meir Simkha of Dvinsk explains that You shall do no iniquity in justice means that even in pursuit of justice one cannot act with iniquity. For example, one is not allowed to use dishonest scales and measures to recover a debt. Owning an instrument of fraud is prohibited because there is no scenario where using it is permitted: You shall do no iniquity in justice.