As to the Book of Isaiah, in spite of the prevalent opinion that chapters 40-66 were written after the Babylonian captivity, Luzzatto maintained that the whole book was written by Isaiah. He felt that one of the factors that pushed scholars to post-date the latter portion of the book stemmed from a denial of the possibility of prophetic prediction of distant future events, and therefore was a heretical position. Difference of opinion on this point was one of the causes why Luzzatto, after having maintained a friendly correspondence with Rapoport, turned against the latter. Another reason for the interruption of his relations with the chief rabbi of Prague was that Luzzatto, though otherwise on good terms with Jost, could not endure the latter's extreme rationalism. He consequently requested Rapoport to cease his relations with Jost; but Rapoport, not knowing Luzzatto personally, ascribed the request to arrogance.