The story of Daniel is fulfillment of the prophecy in Isaiah chapter 39. Thus Daniel sits in slot 39 of the book order as the last book of the Old Testament. That Daniel is the end of the Old Testament is curious considering it's regularly studied in tandem with Revelation, the last book of the New Testament.
There are several matches between Isaiah 39 and Daniel, but the passages do not lend themselves to quoting in small bits so I've just provided two longer quotes and followed up with notes below.
| Isaiah | Daniel |
|---|---|
|
13 Isaiah 39:1-40:0
|
39 Daniel 1:1-4 |
One of the obvious matches beween Isaiah 39 and Daniel is the theme of Babylon. Hezekiah is visited by envoys from Babylon and is given a word that his kingdom is eventually going there. Daniel begins with people and treasures and all being hauled to Babylon. So the word was fulfilled.
Something you don't know from reading the book of Daniel or anywhere else in Scripture is that Daniel is a descendent of Hezekiah. You know from reading the book of Daniel that Daniel had been in the royal court, but that alone does not prove his lineage back to Hezekiah. With Daniel and Isaiah 39 matched it's clear that at least Daniel is in view when God spoke to Hezekiah about his descendents.
Hezekiah is told that his sons would become eunuchs in Babylon. It's not in the Daniel quote above, but if you read further in Daniel chapter 1, Daniel and his friends are in the care of a guy who is chief of the eunuchs. That means Daniel was a eunuch in Babylon and a second aspect of the word Isaiah spoke is fulfilled in Daniel's story.
The other matching component that's in both passages is this theme of treasures. Hezekiah was not discrete with his treasures and so the word came from Yahvah that those treasures would eventually be taken to Babylon. The book of Daniel begins with the story of some of the temple articles and other treasures being taken to Babylon. So the word came true on this third point also.
All in all it's quite clear we're looking at Daniel when we read Isaiah 39.