Perfect Physical Health
By fulfilling a mitzvah you impart life to the limb or organ with which you do the mitzvah. If you fail to do a mitzvah, the limb that is associated with this mitzvah will be deprived of its life-force and will become deceased.
Now, when a person is ill, if he is uninformed as to the true source of his sickness, he will consult a physician who may not restore his health. But if he would turn to the Book of Healing - the Torah - and examine his actions and search for his failings he would not need to undergo the lengthy therapy of the human doctor; his cure would arrive instantly. He would achieve not only perfect physical health but also prosperity and a happy family life.
(Rebbe Menachem Nachum of Chernobyl)