Moshe takes out Yosef’s remains, he does this 1) because they swore not to leave without them 2) Because it gave us -Yidden the strength needed to survive the Midbar.
The Rebbe takes an old and obscure idea and makes it shine. In this case, the Tzemach Tzedek’s mention that Yosef was named Yosef to denote making from an אחר, a foreigner, a בן, a son for Hashem.
Inside// going into the desert requires special strength that comes from Yosef.
