Al-Kāfi - Volume 3 > Recitations in Salah (prayer)
Hadith #20

20ـ مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنِ الْحُسَيْنِ بْنِ سَعِيدٍ عَنِ الْقَاسِمِ بْنِ مُحَمَّدٍ عَنْ صَفْوَانَ الْجَمَّالِ قَالَ صَلَّيْتُ خَلْفَ أَبِي عَبْدِ الله (عَلَيْهِ الْسَّلام) أَيَّاماً فَكَانَ إِذَا كَانَتْ صَلاَةٌ لاَ يُجْهَرُ فِيهَا جَهَرَ بِ بِسْمِ الله الرَّحْمنِ الرَّحِيمِ وَكَانَ يَجْهَرُ فِي السُّورَتَيْنِ جَمِيعاً.

20. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from al-Husayn ibn Sa’id from al-Qasim ibn Muhammad from Safwan al-Jammal who has said the following: “I performed Salah (prayer) for many days in congregation led by abu ‘Abd Allah, ‘Alayhi al-Salam, and in Salah (prayer) which is not recited loudly, he would read Bismillah, (in the name of Allah, most Beneficent, most Merciful) aloud in both Surah (chapters).”