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

4ـ أَحْمَدُ بْنُ مُحَمَّدٍ عَنِ الْحُسَيْنِ بْنِ سَعِيدٍ عَنِ الْحَسَنِ عَنْ سُلَيْمَانَ الْجَعْفَرِيِّ قَالَ قَالَ أَبُو الْحَسَنِ (عَلَيْهِ السَّلاَم) صَلِّ لَيْلَةَ إِحْدَى وَعِشْرِينَ وَلَيْلَةَ ثَلاثٍ وَعِشْرِينَ مِائَةَ رَكْعَةٍ تَقْرَأُ فِي كُلِّ رَكْعَةٍ قُلْ هُوَ الله أَحَدٌ عَشْرَ مَرَّاتٍ.

4. Ahmad ibn Muhammad has narrated from al-Husayn ibn Sa‘id from al-Hassan from Sulayman al-Ja’fariy who has said the following: “Abu al-Hassan, ‘Alayhi al-Salam, has said, ‘In the twenty- first and twenty-third nights, you should perform salat (prayer) of one hundred Rak’ats and in each Rak’at read Chapter 112 of the Holy Quran ten times.’”