question #1 Sahih al-Bukhari 340, Book 7, Hadith 7 : What is the significance of performing tayammum in the absence of water for purification in Islam?

that while he was in the company of `Umar, `Ammar said to `Umar, “We were in a detachment and
became Junub and I blew the dust off my hands (performed the rolling over the earth and prayed.)”