question #1 Sahih al-Bukhari 341, Book 7, Hadith 8 : What is the significance of tayammum in Islamic practice when water is not available?

`Ammar said to `Umar “I rolled myself in the dust and came to the Prophet (ﷺ) who said, ‘Passing dusted
hands over the face and the backs of the hands is sufficient for you.’ ”