Al-Kāfi
Hadith 13926ـ عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ مُحَمَّدِ بْنِ عِيسَى عَنْ يُونُسَ عَنِ الْعَلاَءِ بْنِ رَزِينٍ عَنْ مُحَمَّدِ بْنِ مُسْلِمٍ عَنْ أَحَدِهِمَا (عَلَيْهِما الْسَّلام) قَالَ سَأَلْتُهُ عَنِ السَّهْوِ فِي النَّافِلَةِ فَقَالَ لَيْسَ عَلَيْهِ شَيْءٌ.
6. Ali ibn Ibrahim has narrated from Muhammad ibn ‘Isa from Yunus fro, af-‘Ala’ ibn Razin from Muhammad ibn Muslim who has said the following: “I once asked one of the two Imam, ‘Alayhim al-Salam, about mistakes in optional Salah (prayer). He (the Imam) said, ‘There is not anything upon him.’”