Musnad Ahmad 27:553

Abu Mu'awiyah narrated to us, Laith narrated to us, from Mujahid, from Ibn Umar, who said: The Messenger of Allah (peace and blessings of Allah be upon him) took hold of my garment or some part of my body and said: "O Abdullah, be in this world as if you were a stranger or a passerby, and count yourself among the people of the graves."