Al-Kāfi

Hadith 800
oaths-vows
1- مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنْ عَلِيِّ بْنِ الْحَكَمِ عَنْ هِشَامِ بْنِ سَالِمٍ عَنْ أَبِي عَبْدِ اللهِ (عَلَيْهِ السَّلام) قَالَ لا يَحْلِفُ الرَّجُلُ إِلا عَلَى عِلْمِهِ.
1. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from Ali ibn al-Hakam from Hisham ibn Salim who has narrated the following: “Abu ‘ Abd Allah (a.s.), has said, ‘A man must not take an oath except for what he knows. 5 ”
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī