Musannaf Ibn Abi Shaybah

It is narrated from Hazrat Ka'b that he says the Messenger of Allah, peace and blessings be upon him, said: The example of a believer is like a fresh crop which the winds move; sometimes they bend it and sometimes they straighten it, until it turns yellow. And the example of a disbeliever is like a pine tree which stands straight on its root in the ground; nothing can move it until it is uprooted all at once.