Hadithcore
Sahih al-Bukhari, 188
sahih

Abu Musa said:

The Prophet (ﷺ) asked for a tumbler containing water and washed both his hands and face in it and then threw a mouthful of water in the tumbler and said to both of us (Abu Musa and Bilal), "Drink from the tumbler and pour some of its water on your faces and chests."

وَقَالَ أَبُو مُوسَى دَعَا النَّبِيُّ صلى الله عليه وسلم بِقَدَحٍ فِيهِ مَاءٌ، فَغَسَلَ يَدَيْهِ وَوَجْهَهُ فِيهِ، وَمَجَّ فِيهِ ثُمَّ قَالَ لَهُمَا اشْرَبَا مِنْهُ، وَأَفْرِغَا عَلَى وُجُوهِكُمَا وَنُحُورِكُمَا‏.‏

Isnad

1 transmitter
References2 variants
In-Book Reference
Book 4, Hadith 54
USC-MSA web (English) reference
Vol. 1, Book 4, Hadith 187 (deprecated numbering scheme)