Why does the Torah break off the narrative here, to discuss the lineage of Reuven, Shimon and Levi?
Rashi #1, Rashbam #1 and Seforno: It is important at this juncture to present the Yichus of Levi on account of Moshe and Aharon. 1 And it would not have been befitting to begin with Levi, 2 so it begins with Reuven.
Rashi #2 (citing the Pesikta Gedolah) and Rashbam #2 (citing the Mechilta): The Torah makes a point of presenting the lineage of Reuven Shimon and Levi, to demonstrate their importance, since Ya'akov berated them before his death.
Why does the Torah tell how long Levi lived?