Hazrat Ubaid bin Khalid radiyallahu anhu says, "I was once going to Madinah Munawwarah. I heard a person from behind me say, "Wear the lungi higher because it avoids physical and spiratual najaasah (impurities)." (The lungi will remain cleaner and will not become dirty by being dragged on the ground.)When I turned to see who was talking, I saw that it was Rasoolullah sallallahu alaihe wasallam. I said, "O' Rasoolullah, this is a simple lungi, how can one become proud, and it is necessary to look after it (keep it clean)?"Rasoolullah sallallahu alaihe wasallam replied, "If you see no benefit in it, your following me has not ceased."While Rasoolullah sallallahu alaihe wasallam was telling me this, I saw that his lungi reached till half his him."
English reference: Book 17, Hadith 113
Arabic reference: Book 18, Hadith 120