Al-Kāfi
Hadith 7692- عِدَّةٌ مِنْ أَصْحَابِنَا عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنْ عُثْمَانَ بْنِ عِيسَى عَنْ أَبِي أَيُّوبَ الْخَزَّازِ عَنْ أَبِي عَبْدِ اللهِ (عَلَيْهِ السَّلام) قَالَ مَنْ حَلَفَ بِاللهِ فَلْيَصْدُقْ وَمَنْ لَمْ يَصْدُقْ فَلَيْسَ مِنَ اللهِ وَمَنْ حُلِفَ لَهُ بِاللهِ عَزَّ وَجَلَّ فَلْيَرْضَ وَمَنْ لَمْ يَرْضَ فَلَيْسَ مِنَ اللهِ عَزَّ وَجَلَّ.
2. A number of our people have narrated from Ahmad ibn Muhammad from ‘Uthman ibn ‘Isa from abu Ayyub al-Khazzaz who has narrated the following: “Abu ‘Abd Allah, Alayhi al-Salam, has said, ‘If one swears by Allah it must be considered true, if one does not believe he is not of Allah. One must agree with an oath by Allah, if he does do so he is not of Allah, most Majestic, most Glorious.’”