In the book of Esther it never says to people that live in walled cities to make Purim on the 15th. All it says is Jews that live in unwalled cities make it on the 14th and then right away goes on to say that Mordecai sent letters throughout Peria to make Purim on the 14 and the 15th. It says nothing about Jews that live in walled cities. This might account for the fact that Rav Nahman of Breslov said that Shushan Purim is also Purim.
[The way I noticed this is because right after the verse saying that Jews in un-walled cities make Purim on 14th you expect it to say something about Jews in walled cities. But instead it simply skips the subject.]
[The way I noticed this is because right after the verse saying that Jews in un-walled cities make Purim on 14th you expect it to say something about Jews in walled cities. But instead it simply skips the subject.]
