Abu Dawud Book 27, Hadith Number 4085.

Chapter : Upto what extent one should wear the lower garment.

Narated By Abdullah ibn Abbas : Ikrimah said that he saw Ibn Abbas putting on lower garment, letting the hem on the top of his foot and raising it behind. He said: Why do you put on the lower garment in this way? He replied: It is how I saw the Apostle of Allah (PBUH) do it.