Description of the Prayer from Its Beginning to Its End
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 46
وَ رَوَى مُحَمَّدُ بْنُ مُسْلِمٍ عَنْ أَبِي جَعْفَرٍ عَلَيْهِ اَلسَّلاَمُ أَنَّهُ قَالَ: «اَلْقُنُوتُ فِي كُلِّ رَكْعَتَيْنِ فِي اَلتَّطَوُّعِ وَ اَلْفَرِيضَةِ.
Muhammad ibn Muslim narrated from Imam Muhammad ibn Ali Al-Baqir عليه السلام that He said: "The Qunoot (supplication) is in every two units of both voluntary and obligatory prayers."
- Ṣaḥīḥ al-Faqīh, p. 45