The Prayer for Seeking Rain (Salat Al-Istisqa)
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 80
وَقَالَ أَبُو جَعْفَرٍ عَلَيْهِ اَلسَّلاَمُ: «كَانَ رَسُولُ اَللَّهِ صَلَّى اَللَّهُ عَلَيْهِ وَ آلِهِ يُصَلِّي لِلاِسْتِسْقَاءِ رَكْعَتَيْنِ وَ يَسْتَسْقِي وَ هُوَ قَاعِدٌ» وَقَالَ «بَدَأَ بِالصَّلاَةِ قَبْلَ اَلْخُطْبَةِ وَ جَهَرَ بِالْقِرَاءَةِ.
Imam Muhammad ibn Ali Al-Baqir عليه السلام said: "The Messenger of Allah صلى الله عليه وعلى آله وسلم would perform two Rak'ahs of prayer for rain (Istisqa') and supplicate for rain while seated." He also said: "He began with the prayer before the sermon and recited aloud."
- Ṣaḥīḥ al-Faqīh