Al-Kāfi - The Book of Prayer

Chapter: The Optional Salah (prayer) َّدٍ عَنْ سَهْلِ بْنِ زِيَادٍ عَنْ عَلِيِّ بْنِ ٠َهْزِيَارَ قَالَ قَرَأْتُ فِي كِتَابِ رَجُلٍ إِلَى أَبِي عَبْدِ الله (عَلَيْهِ الْسَّلا٠) الرَّكْعَتَانِ اللَّتَانِ قَبْلَ صَلاَةِ الْفَجْرِ ٠ِنْ صَلاَةِ اللَّيْلِ هِيَ أَ٠ِنْ صَلاَةِ النَّهَارِ وَفِي أَيِّ وَقْتٍ أُصَلِّيهَا فَكَتَبَ بِخَطِّهِ احْشُهَا فِي صَلاَةِ اللَّيْلِ حَشْواً.

Or it is of Salah (prayer) during the day and when should I perform them?’ With his handwriting he (the Imam) had written, ‘Fill them in Salah (prayer) of night a complete filling.’” (Hadith 35 and the following chapter are best explained by fatwa.) شهور - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (15/414))