Sahih al-Bukhari 1024
Sahih al-Bukhari · Book 15: Invoking Allah for Rain (Istisqaa) · To recite aloud while offering the prayer of Istisqa'
Narrated `Abbad bin Tamim:
حَدَّثَنَا أَبُو نُعَيْمٍ ، حَدَّثَنَا ابْنُ أَبِي ذِئْبٍ ، عَنِ الزُّهْرِيِّ ، عَنْ عَبَّادِ بْنِ تَمِيمٍ ، عَنْ عَمِّهِ ، قَالَ خَرَجَ النَّبِيُّ صلى الله عليه وسلم يَسْتَسْقِي فَتَوَجَّهَ إِلَى الْقِبْلَةِ يَدْعُو، وَحَوَّلَ رِدَاءَهُ، ثُمَّ صَلَّى رَكْعَتَيْنِ جَهَرَ فِيهِمَا بِالْقِرَاءَةِ.
from his uncle who said, "The Prophet (ﷺ) went out to invoke Allah for rain. He faced the Qibla invoking Allah. He turned over his cloak (inside out) and then offered two rak`at and recited the Qur'an aloud in them."