We look at the works of the Sages, the wise Israelite scholars who wrote for a very literate audience.  But the Apostles were not educated people.  At one point, Jesus realizes that since he is about to be gone, and the Apostles will be on their own to spread his Word, it is time to be straightforward and blunt with them.  He conveys a message in simple terms that the Apostles must always remember - and that we must always remember.