Musnad Ahmad 1018:25

Waki’ narrated to us, from Sufyan, from Ash’ath, from his paternal aunt, from her paternal uncle, who said: I was at the market of Dhu al-Majaz, wearing a striped garment of mine that I was dragging. He said: A man poked me with a stick and said, "Raise your lower garment, for it is more lasting and cleaner." I looked, and it was the Messenger of Allah, peace and blessings of Allah be upon him. I looked, and his lower garment was at the midpoints of his shins.