Sayyiduna Ka'b bin Malik (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "The likeness of the believer is that of a tender plant of the crops which the winds keep bending, sometimes straightening it and sometimes laying it down. The likeness of the disbeliever is that of a sturdy cedar tree standing stiffly upon its root, until it is uprooted all at once."
Hadith Referenceالمعجم الكبير للطبراني / باب الكاف / 16233