Language:
كتاب الجمعة
11  
Friday Prayer
(34)
Chapter: To raise hands during the Khutba (religious talk)
(34)
باب رَفْعِ الْيَدَيْنِ فِي الْخُطْبَةِ
Sahih al-Bukhari 932

Narrated Anas:

While the Prophet (ﷺ) was delivering the Khutba on a Friday, a man stood up and said, "O, Allah's Apostle! The livestock and the sheep are dying, so pray to Allah for rain." So he (the Prophet) raised both his hands and invoked Allah (for it).

حَدَّثَنَا مُسَدَّدٌ، قَالَ حَدَّثَنَا حَمَّادُ بْنُ زَيْدٍ، عَنْ عَبْدِ الْعَزِيزِ، عَنْ أَنَسٍ،‏.‏ وَعَنْ يُونُسَ، عَنْ ثَابِتٍ، عَنْ أَنَسٍ، قَالَ بَيْنَمَا النَّبِيُّ صلى الله عليه وسلم يَخْطُبُ يَوْمَ الْجُمُعَةِ إِذْ قَامَ رَجُلٌ فَقَالَ يَا رَسُولَ اللَّهِ، هَلَكَ الْكُرَاعُ، وَهَلَكَ الشَّاءُ، فَادْعُ اللَّهَ أَنْ يَسْقِيَنَا‏.‏ فَمَدَّ يَدَيْهِ وَدَعَا‏.‏
Reference : Sahih al-Bukhari 932
In-book reference : Book 11, Hadith 56
USC-MSA web (English) reference : Vol. 2, Book 13, Hadith 54
  (deprecated numbering scheme)