Al-Kāfi

Hadith 528
trademeasurement
1- عِدَّةٌ مِنْ أَصْحَابِنَا عَنْ أَحْمَدَ بْنَ مُحَمَّدِ بْنِ خَالِدٍ عَنِ ابْنِ فَضَّالٍ عَنِ ابْنِ بُكَيْرٍ عَنْ حَمَّادِ بْنِ بَشِيرٍ عَنْ أَبِي عَبْدِ اللهِ (عَلَيْهِ السَّلام) قَالَ لا يَكُونُ الْوَفَاءُ حَتَّى يَمِيلَ الْمِيزَانُ.
1. A number of our people have narrated from Ahmad ibn Muhammad ibn Khalid from ibn Faddal from ibn Bukayr from Hammad ibn Bashir who has said the following: “Abu ‘ Abd Allah (a.s.), has said, ‘Proper weighing is only when a balance tilts to one side.”’
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī