Jeremiah 36:9 - Ellicott's Commentary On The Whole Bible

It came to pass in the fifth year of Jehoiakim. — The LXX. gives “the eighth year,” but the Hebrew text gives much the more probable date. What follows refers apparently to the same occasion as Jeremiah 36:8, and is of the nature of a note explaining the circumstances under which the prophetic discourse was read. An interval of some months thus passed between the writing of the book and its delivery in the Temple, during which its substance was, perhaps, made known to the inner circle of the prophet’s disciples. The fast was probably proclaimed on the king’s hearing of the approach of Nebuchadnezzar’s army, as described by the Rechabites in Jeremiah 35:11.