Hazrat Ka'b (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: The example of a believer is like that of a tender, weak crop which the wind keeps moving; sometimes it knocks it down and at other times it makes it stand upright, until it dries up. And the example of a disbeliever is like that of a pine tree which stands firm on its roots; nothing can move it until it is uprooted all at once.