From "Toldot" to "Shmot"
Let us now return to our psukim in Parshat Vayigash (46:1-4), i.e. God's promise to be with Yaakov and his family during their stay in Egypt.
Immediately after this final "hitgalut" to Yaakov, the Torah describes the actual journey of the entire family to Egypt (see 46:5-7). The Torah then devotes a special 'parshia' to the enumeration of the seventy members of Yaakov's family:
"These are the names ['v'ayleh shmot'] of Bnei Yisrael who were coming to Egypt..." (46:8)This special 'parshia' - "v'ayleh shmot..." - marks the conclusion of the "bechira" process of Sefer Breishit, as it is from these seventy "nefesh" (souls) that the Jewish nation will develop. (See Board #2.) The process of "bechira" which has progressed through the choosing of specific "toladot" is now complete. The chosen family is now presented as "shmot."
This may explain why Sefer Shmot begins with the very same phrase. In fact, its opening psukim (1:1-4) actually summarize this 'parshia' (i.e. 46:8-27). Furthermore, the first primary topic of Sefer Shmot is the fulfillment of Brit Bein Ha'Btarim - the story of how these seventy people multiply, become a multitude, are enslaved and then redeemed.
The remainder of Sefer Breishit (46:28-50:26) completes details of the relationship among the brothers, their dwelling in Egypt, the deaths of Yaakov and Yosef, etc. Sefer Shmot, which discusses God's fulfillment of Brit Bein Ha'btarim, begins with "v'ayleh shmot Bnei Yisrael..." - right where the primary theme of Sefer Breishit left off. From these seventy souls God's special Nation will emerge.