question #1 Sahih al-Bukhari 188, Book 4, Hadith 54 : What is the significance of using water that the Prophet (ﷺ) has used for washing in Islamic tradition?

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.”