وإن في الجسد مضغة إذا صَلَحَتْ صَلَحَ الجسدُ كله وإذا فَسَدَتْ فسدَ الجسدُ كله ألا وهي القَلْب صحيح مسلم Indeed in the body there is a lump of flesh, if it is good, the entire body will be good, and if it is corrupted, the entire body becomes corrupted, and that is the heart.