Shu`ayb says to his people:وَيَا قَوْمِ أَوْفُواْ الْمِكْيَالَ وَالْمِيزَانَ بِالْقِسْطِوَلَا تَبْخَسُواْ النَّاسَ أَشْيَاءهُمْ وَلَا تَعْثَوْاْ فِي الَارْضِ مُفْسِدِينَ"And O my people! Give full measure and weight in justice and reduce not the things that are due to the people, and do not commit mischief in the land, causing corruption." First, he (Shu`ayb) prohibited them from cheating in business by decreasing the weights whenever they gave (products) to people. He commanded them to give just measure and weight whether they were giving or receiving (in transactions).He also forbade them from causing mischief and corruption in the land. This was due to their practice of highway robbery along the roads