Why do you have to go back to Revelation when studying Daniel?
When studying Daniel, one must go back to Revelation because the two books are so intertwined. They are next of kin, and both were written from outside of Israel, so each book requires the other for proper understanding. This back-and-forth comparison keeps the study of these books in context.
Les teaches that Daniel and Revelation are so intertwined that whenever you study Daniel, you must go back to Revelation, and whenever you study Revelation, you must go back to Daniel. Both were written from outside Israel, which ties them closely together. He also draws an analogy to the twelve apostles, who were chosen within Israel, and Paul, who was called on Gentile ground outside Damascus, showing the drastic difference and why being outside Israel matters.