Hadith 25

Sahih Bukhari

Book 15: Invoking Allah for Rain (Istisqaa)

Chapter 21

While offering the Istisqa' prayer, people should raise hands along with the Imam

باب رَفْعِ النَّاسِ أَيْدِيَهُمْ مَعَ الإِمَامِ فِي الاِسْتِسْقَاءِ

Sahih al-Bukhari 1030
وَقَالَ الأُوَيْسِيُّ حَدَّثَنِي مُحَمَّدُ بْنُ جَعْفَرٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، وَشَرِيكٍ، سَمِعَا أَنَسًا، عَنِ النَّبِيِّ صلى الله عليه وسلم أَنَّهُ رَفَعَ يَدَيْهِ حَتَّى رَأَيْتُ بَيَاضَ إِبْطَيْهِ‏.‏
The narrator Anas added that the Prophet (ﷺ) raised his hands (during the invocation) to such an extent that the whiteness of his armpits was visible.