Musnad Ahmad 33:644

Musa and Hasan narrated to us, they said: Ibn Lahi'ah narrated to us, from Abu al-Zubayr, from Jabir, that the Prophet, peace and blessings of Allah be upon him, said: "The likeness of the believer is like the stalk of grain; it falls one time and stands straight another time. And the likeness of the disbeliever is like the cedar tree; it remains straight until it falls, and it does not perceive." Hasan said: The cedar tree (al-arzah).