Description of the Prayer from Its Beginning to Its End
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 46
وَ سَأَلَ اَلْحَلَبِيُّ أَبَا عَبْدِ اَللَّهِ عَلَيْهِ اَلسَّلاَمُ: عَنِ اَلْقُنُوتِ فِيهِ قَوْلٌ مَعْلُومٌ فَقَالَ «أَثْنِ عَلَى رَبِّكَ وَ صَلِّ عَلَى نَبِيِّكَ وَ اِسْتَغْفِرْ لِذَنْبِكَ.
Al-Halabi asked Imam Jafar ibn Muhammad Al-Sadiq عليه السلام about what should be said in the Qunoot (the supplication during prayer). Imam عليه السلام replied: "Praise your Lord عز وجل, send blessings upon your Prophet, and seek forgiveness for your sins."
- Ṣaḥīḥ al-Faqīh, p. 45