Abu Dawud Book 27, Hadith Number 4074.

Chapter : Hanging down the lower garment below the ankles.

Narated By N/A : Ibn ‘Umar reported the Apostle of Allah (may peace be upon him) as saying: If anyone trails his garment arrogantly, Allah will not look at him on the Day of Resurrection. Then Abu Bakr said: One of the sides of my lower garment trails, but still I remain careful about it. He said: You are not one of those who do so conceitedly.