Why does the Torah literally state; "And the life of Sarah was 100 years and 20 years and 7 years"? (Bereishit - Genesis 23:1). It's a strange way to recount the terminal age of the matriarch. But, something more intriguing ocurs at this juncture, the foundation of the Jewish nation. Two woman bound together by the life of Isaac; son, husband and patriarch who never left the land of his inherritance.
At the outset of the verse, the first word וַיִּהְיוּ֙ (Va'-Yi-h-Yu) is a palindrome with a numerical value of 37 that captures the age of Isaac at Sarah's death, which Rashi said ocurred when Abraham offered Isaac as a sacrifice. The word connects previous details on which Rashi comments; the entire genealogy was recorded only to tell that Rebecca was born to Betuel".
Comentators highlight the rarity of the recorded deaths of women. Only Sarah, Devorah (Rebecca's wet nurse), Rachel and ~500 years later Miriam. Rebecca's passing is not mentioned at all and years are mentioned only for Sarah, perhaps to emphasize her importance and Rebecca's humility.
Two events shaped the destiny of the Jewish people thanks to the conviction of matriarchs Sarah and Rebecca. Sarah banished Hagar and Ishmael from her family, causing the inherritance of Abraham's first born to pass to Isaac instead. And, 120 years later Rebecca instructed Jacob decieve Isaac to obtain the blessing normally held for their first born son Esau.
Finally, immediately after Devorah passed and was burried, Rebecca passed and Rachel gave birth to Benjamin, the only child of Jacob to be born in Israel before she passed during childbirth.
The decision of Sarah and Rebecca to uphold Jewish life, to separate Isaac and Jacob from powerful dissipating forces were determinative. For that Jews have paid a heavy price. By their actions the passage of souls into the world had been completed and the destiny of Jewish generations set in place through the end of days.