Musnad Ahmad 27:1803

Muhammad ibn Abd al-Rahman al-Tafawi narrated to us, Ayyub narrated to us, from Zayd ibn Aslam, from Ibn Umar, who said: I entered upon the Prophet, may Allah bless him and grant him peace, while I was wearing an izar (lower garment) that was rustling. He said: "Who is this?" I said: "Abdullah ibn Umar." He said: "If you are Abdullah, then raise your izar." So I raised my izar to the middle of my shins. And his izar remained that way until he died.