Musannaf Ibn Abi Shayba 33:186

Narrated to us Abd al-A'la, from Ma'mar, from al-Zuhri, from Sa'id, from Abu Hurayrah, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: The likeness of the believer is like the crop; the wind does not cease to incline it, and the believer does not cease to be afflicted by trials. And the likeness of the disbeliever is like the cedar tree; it does not shake until it is harvested.