Sahih al-Bukhari 1029
Sahih al-Bukhari · Book 15: Invoking Allah for Rain (Istisqaa) · While offering the Istisqa' prayer, people should raise hands along with the Imam
Narrated Anas bin Malik:
قَالَ أَيُّوبُ بْنُ سُلَيْمَانَ حَدَّثَنِي أَبُو بَكْرِ بْنُ أَبِي أُوَيْسٍ، عَنْ سُلَيْمَانَ بْنِ بِلاَلٍ، قَالَ يَحْيَى بْنُ سَعِيدٍ سَمِعْتُ أَنَسَ بْنَ مَالِكٍ، قَالَ أَتَى رَجُلٌ أَعْرَابِيٌّ مِنْ أَهْلِ الْبَدْوِ إِلَى رَسُولِ اللَّهِ صلى الله عليه وسلم يَوْمَ الْجُمُعَةِ فَقَالَ يَا رَسُولَ اللَّهِ، هَلَكَتِ الْمَاشِيَةُ هَلَكَ الْعِيَالُ هَلَكَ النَّاسُ. فَرَفَعَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَدَيْهِ يَدْعُو، وَرَفَعَ النَّاسُ أَيْدِيَهُمْ مَعَهُ يَدْعُونَ، قَالَ فَمَا خَرَجْنَا مِنَ الْمَسْجِدِ حَتَّى مُطِرْنَا، فَمَا زِلْنَا نُمْطَرُ حَتَّى كَانَتِ الْجُمُعَةُ الأُخْرَى، فَأَتَى الرَّجُلُ إِلَى نَبِيِّ اللَّهِ صلى الله عليه وسلم فَقَالَ يَا رَسُولَ اللَّهِ، بَشِقَ الْمُسَافِرُ، وَمُنِعَ الطَّرِيقُ.
A bedouin came to Allah's Messenger (ﷺ) on a Friday and said, "O Allah's Messenger ! The livestock, the offspring, and the people have perished." So, Allah's Messenger (ﷺ) raised both his hands invoking Allah (for rain) and the people too raised their hands with Allah's Messenger (ﷺ) invoking Allah (for rain). We had not left the mosque when it started raining. It rained till the next Friday when the same man came to Allah's Messenger (ﷺ) and said, "O Allah's Messenger! The travelers are compelled to postpone their journeys (because of excessive rain) and the roads are overflowed."