Bukhari Collection: ::Book Number 5:: Hadith # 40
Narrated Abu Sa`id Al-Khudri:I heard Allah's Apostle saying, "While I was sleeping, the people were presented to me (in a dream). They were wearing shirts, some of which were merely covering their (chests). and some were a bit longer. `Umar was presented before me and his shirt was so long that he was dragging it." They asked, "How have you interpreted it, O Allah's Apostle?" He said, "Religion."