Al-Kāfi - Volume 4 > Additional Salat (prayer) in the Month of Ramadan
Hadith #5

5ـ عَلِيُّ بْنُ مُحَمَّدٍ عَنْ صَالِحِ بْنِ أَبِي حَمَّادٍ عَنِ الْحَسَنِ بْنِ عَلِيٍّ عَنِ ابْنِ سِنَانٍ عَنْ أَبِي شُعَيْبٍ الْمَحَامِلِيِّ عَنْ حَمَّادِ بْنِ عُثْمَانَ عَنِ الْفُضَيْلِ بْنِ يَسَارٍ قَالَ كَانَ أَبُو جَعْفَرٍ (عَلَيْهِ السَّلاَم) إِذَا كَانَتْ لَيْلَةُ إِحْدَى وَعِشْرِينَ وَلَيْلَةُ ثَلاثٍ وَعِشْرِينَ أَخَذَ فِي الدُّعَاءِ حَتَّى يَزُولَ اللَّيْلُ فَإِذَا زَالَ اللَّيْلُ صَلَّى.

5. Ali ibn Muhammad has narrated from Salih ibn abu Hammad from al-Hassan ibn Ali from ibn Sinan from abu Shu’ayb al-Muhamiliy from Hammad ibn ‘Uthman from al-Fudayl ibn Yasar who has said the following: “Abu Ja’far, ‘Alayhi al-Salam, during the twenty-first and twenty-third nights, would pray until the end of the night, then perform (the obligatory) salat (prayer).”