I have heard many times that there will always be at least one illness that is uncurable. Is this a Jewish idea? What is its source?
I'm thinking no because in Sefer Nishmat Avraham- Orach Chaim Siman 1 it is written: "Indeed, Chazal stated: The Holy One, Blessed be He, said: There is no illness for which a complete cure is not already present.
The footnote says(I'm translating from Hebrew) Tanchumah Yitro Chet