The Context

The Tzemach Tzedek records that his grandfather, the Alter Rebbe, passed away on Motzei Shabbos Shemos before midnight, while he was exiled from his home as he fled the French forces. Clearly, by tying the Alter Rebbe’s passing to Shemos and to his being in exile, the Tzemach Tzedek means to underscore a thematic connection between the two.