The Rebbe's Last Maamar
Take for yourself this pure olive oil,Vol. 6

Maamarim of the Lubavitcher Rebbe,
Rabbi Menachem M. Schneerson
by Rabbi Yosef Shusterman

This maamar is based on the pasuk "And you shall command the children of Israel and they shall bring you pure olive oil, crushed for the light, to keep a constant lamp burning." It discusses how a Rebbe is able to bring out the essence of a Jew in difficult times.