Qur'ān 17:35 · Al-Isra (الإسراء)

وَأَوْفُوا۟ ٱلْكَيْلَ إِذَا كِلْتُمْ وَزِنُوا۟ بِٱلْقِسْطَاسِ ٱلْمُسْتَقِيمِ ۚ ذَٰلِكَ خَيْرٌۭ وَأَحْسَنُ تَأْوِيلًۭا

And give full measure when you measure, and weigh with an even balance. That is the best [way] and best in result.