Al-Kāfi
Hadith 19732ـ عِدَّةٌ مِنْ أَصْحَابِنَا عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنْ عُثْمَانَ بْنِ عِيسَى قَالَ سَأَلْتُ أَبَا الْحَسَنِ (عَلَيْهِ السَّلاَم) عَنْ إِتْمَامِ الصَّلاةِ وَالصِّيَامِ فِي الْحَرَمَيْنِ فَقَالَ أَتِمَّهَا وَلَوْ صَلاةً وَاحِدَةً.
2. A number of our people have narrated from Ahmad ibn Muhammad from ‘Uthman ibn ‘Isa who has said the following: “I once asked abu al-Hassan (a.s.), about performing Salat (prayer) in complete form and fasting in the two al-Haram (the sacred places); Masjid al-Haram and Masjid of al-Madinah. He (the Imam) said, ‘You should perform Salat (prayer) in complete form, even if it is one Salat (prayer).”’