Sahih al-Bukhari 188
Abu Musa said:
The 
Prophet 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.‏