Tafsir of Ar-Rahman 55:8

أَلَّا تَطْغَوْا فِي الْمِيزَانِ (so that you should not be wrongful in weighing....55:8). The earlier verse stated the creation of the scale, and this verse states the reason for its creation. The imperfect verb تَطْغَوْا tatghaw is derived from طُغیَان tughyan which stands for 'injustice'. Thus verses [ 7] and [ 8] put together mean: '[ The 'mizan or scale' has been created so that you may not transgress the balance and thus practice injustice'.