Al-Kāfi
Hadith 5325- عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنِ ابْنِ أَبِي عُمَيْرٍ عَنْ غَيْرِ وَاحِدٍ عَنْ أَبِي عَبْدِ اللهِ (عَلَيْهِ السَّلام) قَالَ لا يَكُونُ الْوَفَاءُ حَتَّى يَرْجَحَ.
5. Ali ibn Ibrahim has narrated from his father from Ibn Abi ‘Umayr from more than one person who has said the following: “Abu ‘Abd Allah (a.s.), has said, ‘It is not a proper weighing until a side of balance tilts.’”