Language:
كتاب الغسل
5
Bathing (Ghusl)
(9)
Chapter: Can a Junub (a person who has yet to take bath after the sexual act or wet dream) put his hands in a pot (containing water) before washing them if they are not polluted with a dirty thing except Janaba?
(9)
باب هَلْ يُدْخِلُ الْجُنُبُ يَدَهُ فِي الإِنَاءِ قَبْلَ أَنْ يَغْسِلَهَا إِذَا لَمْ يَكُنْ عَلَى يَدِهِ قَذَرٌ غَيْرُ الْجَنَابَةِ
Sahih al-Bukhari 261

Narrated Aisha:

The Prophet (ﷺ) and I used to take a bath from a single pot of water and our hands used to go in the pot after each other in turn.

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ، أَخْبَرَنَا أَفْلَحُ، عَنِ الْقَاسِمِ، عَنْ عَائِشَةَ، قَالَتْ كُنْتُ أَغْتَسِلُ أَنَا وَالنَّبِيُّ، صلى الله عليه وسلم مِنْ إِنَاءٍ وَاحِدٍ تَخْتَلِفُ أَيْدِينَا فِيهِ‏.‏
Reference : Sahih al-Bukhari 261
In-book reference : Book 5, Hadith 14
USC-MSA web (English) reference : Vol. 1, Book 5, Hadith 261
  (deprecated numbering scheme)