وَأَوْفُوا۟ ٱلْكَيْلَ إِذَا كِلْتُمْ وَزِنُوا۟ بِٱلْقِسْطَاسِ ٱلْمُسْتَقِيمِ ۚ ذَٰلِكَ خَيْرٌ وَأَحْسَنُ تَأْوِيلًا Qur’an Al-Israa (17:35)Waawfoo alkayla i tha kiltum wazinoo bi a lqis ta si almustaqeemi tha lika khayrun waa h sanu taweel a n
Lit., "straight" (mustaqim)-a term which in the Qur'an has invariably a spiritual or moral connotation. Hence, as in the similar phrase in {6: 152}, the above injunction applies not merely to commercial transactions but to all dealings between man and man.
Giving just measure and weight is not only right in itself but is ultimately to the best advantage of the person who gives it.