Mesirus Nefesh in today’s times:
In previous times, when persecution of Jews and Judaism was common, the Mesirus Nefesh in service of G-d was in the most literal sense, to give up one’s life to serve G-d. In current times where most Jews live in democratic countries which provide freedom of religion the Mesirus Nefesh required is on a different scale. One’s Mesirus Nefesh today involves not being affected by the words of scoffers and continuing his service of G-d despite the common public consensus which ridicules his method of life.
Moshe was humbled by our Mesirus Nefesh: The Alter Rebbe taught that the humility of Moshe which surpassed the humility of all other people was mainly affected by his foreseeing the challenges that the Jews in the time of the footsteps of Moshiach would face and succeed. When he saw the Mesirus Nefesh in which the Jews at that time would serve Hashem against all the concealments and public ridicule he became humbled in his own service.
 Toras Menachem 3 p. 157; See also Mamar “Ein Hakadosh Baruch Hu Ba Betrunya” 5648 for a thorough overview of the Mesirus Nefesh required in today’s times against the scoffers. The Rebbe Rayatz instructed the students of Tomchei Temimim to commit this Mamar to memory. [Sefer Hamamarim 5685 p. 7]
 Mamar Yud Kisleiv 1941 [Mamarim Melukatim 2 p. 51]