The section of the Babylonian Esther Midrash quoted by Shai in his post has a parallel in Vayikrah Rabbah and in the Pesikta de-Rav Kahana (Vayikrah Rabbah 28:6 [664-666]):
Eyal Ben-Eliyahu, Between Borders: The Boundaries of Eretz-Israel in the Consciousness of the Jewish People in the time of the Second Temple and in the Mishnah and Talmud Period, Jerusalem: Yad Ben-Zvi Press, 2012, 348 pp. $27.
Eyal Ben-Eliyahu‘s Between Borders is the kind of book which deals with such fundamental questions that it makes you wonder how it is that they had not been seriously addressed before. Based on his 2007 Hebrew University dissertation, the book aims to examine the territorial borders of the land of Israel as reflected in a wide array of Palestinian texts – from biblical books through the Amoraic era – and tries to formulate the different concepts of “Eretz Israel” that these borders represent.