It states (15:26) אלקיך 'ה לקול תשמע שמוע אם ויאמר כל חקיו כל ושמרת למצותיו והאזנת תעשה בעיניו והישר רפאך 'ה אני כי עליך אשים לא במצרים שמתי אשר המחלה, "[Hashem] said, 'If you hearken diligently to the voice of Hashem, your G-d, and do what is just in His eyes, give ear to His commandments and observe all His decrees, then any of the diseases that I placed in Egypt, I will not bring upon you, for I am Hashem, your Healer."
There seems to be a contradiction in the pasuk. It states that we won't become ill, and afterward, it states רפאך 'ה אני כי, that Hashem will heal us. Why do we need to be healed if we don't become ill? (See Rashi).
The Yaavutz explains that there are illnesses within us every day, but Hashem heals us each day so the diseases don't develop and take over the health of the person's body. Hashem promises that we won't become ill because He is always curing us before we become aware of the illness within us.
The Yaavutz explains that this is the reason we say ונרפא 'ה רפאנו every day in Shemonah Esrei. We need to daven for a refuah every day, because every day we are ill, and every day Hashem heals us.
The Gemara (Yoma 22:) says ולא חלי לא כמה סייעיה דמריה גברא מרגיש. Rashi translates it, כמה ה''שהקב מי רעה מכל ולדאג לחלות צריך ואין ומובטח סמוך בעזרו. This means that if you are a person whom Hashem is helping, you have nothing to worry about. Hashem will take care of all your needs.
Rebbe Pinchas Ustilla zt'l said that we can also translate it as follows: חלי לא כמה, as long as a person hasn't become ill, מרגיש ולא סייעיה דמריה גברא, he doesn't realize that Hashem is helping him. He takes his health for granted and doesn't recognize that he must praise Hashem for his health.
Rebbe Shlomo Tchortkover zt'l (niftar year 5717) was diagnosed on Tu b'Shvat with the known 'disease.' Growths were found on his body. On Shabbos, parashas Bishalach, he said at his tish, "I never understood the pasuk (15:26) בעיניו והישר אלקיך 'ה לקול תשמע שמוע אם אני כי עליך אשים לא במצרים שמתי אשר המחלה כל ...תעשה רפאך 'ה, "If you hearken diligently to the voice of Hashem, your G-d, and do what is just in His eyes...then any of the diseases that I placed in Egypt, I will not bring upon you, for I am Hashem, your healer.' It seems like a small reward for keeping the entire Torah. Why is not becoming ill considered a valid reward for keeping the Torah? But now I understand that being healthy is the greatest reward. When someone is ill, he is prepared to give away everything he owns to become well. He would pay billions to get better. The pasuk concludes רופאך 'ה אני, because Hashem is healing us all the time, only we aren't aware of it."
This teaches us two lessons: It reminds us that we should daven that we remain healthy, as Chazal tell us that one should daven that he doesn't become ill. Furthermore, one should praise Hashem for the health that Hashem gives him.
A child once became ill. The parents, who lived in Eretz Yisrael, brought him to an expert doctor in America. The doctor said that it would cost an enormous price to heal their child. The price was far more than the parents could afford, and they lost hope. The doctors spoke to the child a little, and the child found favor in his eyes. The doctor said to himself, "Because of money, I will let this child die?" He told the parents that he would heal their child for free, and he did so.
When they were ready to return to Eretz Yisrael, now with their healthy son, the father said to the doctor, "I am unable to pay you with money, but if you ever come to Eretz Yisrael and you need something, call me, and I will do whatever I can to help you."
Some years later, the doctor came to Eretz Yisrael, and he was having car trouble in the middle of the night. He remembered that he had a promise from the father of a child he treated that he could call him for any favor. He called him.
At first, the father didn't understand why someone was waking him in the middle of the night, and he responded with harsh words. The doctor told him, "I am the doctor who healed your son. Now I need some help. Won't you help me?"
The lesson is that Hashem does so much kindness to us. He heals us from all our illnesses. There are illnesses within us that we don't even know about, and baruch Hashem, we are healthy and cured of them. If Hashem asks something from us, won't we do His request? This is implied in the pasuk, (15:26) כי ...אלקיך 'ה לקול תשמע שמוע אם ויאמר רפאך 'ה אני, which can be translated, "You should listen to My voice because I heal you. You owe it to me to do what I ask from you when I ask you for a favor."
Reb Noson Gestetner zt'l said that he was once by a dentist and noticed that the dentist was a talmid chacham. "You should be a Rav," Reb Gestetner said. "Why are you a dentist?"
The dentist wittily replied, "I used to be a Rav, but no one listened to me. So, I became a doctor. As a doctor, people listen to me."
Reb Gestetner said that this is implied in the words, (15:26) 'ה לקול תשמע שמוע אם ויאמר רפאך 'ה אני כי ...אלקיך, which can be understood that we should listen to Hashem's voice because Hashem is our doctor, and people listen to doctors' commands.
