The first Pasuk of Chayei Sarah states (23:1), “Vayihiyu Chayei Sarah Mei’ah Shanah VeEsrim Shanah VeSheva Shanim,” “And the [days of] Sarah’s life were one hundred years and twenty years and seven years.”
Rashi says that her years are split up by the word Shanah to show that each age has special significance. At the age of 100, she was like a woman of 20, who is not yet subject to certain heavenly punishments for sins. When she was 20, she was as beautiful as a girl at the age of seven, who is not responsible for sins at all. This would seem to prove that Sarah lived a full and virtuous life.
Ramban, disagreeing with Rashi’s interpretation, quotes a later statement about Avraham (25:7): “VeEilah Yemei Shenei Chayei Avraham Asher Chai, Mei’ah Shanah, VeShiv’im Shanah, VaChamaish Shanim,” “And these are the days of the years of Avraham’s life: one hundred years and seventy years and five years.” Applying Rashi’s idea to this case would not make sense; Avraham could not have been pure for his whole life, since he worshipped idols when he was young. According to Ramban, since Avraham’s years were not meant to be broken up, neither were Sarah’s.
We also see similar phraseology with regard to Yishmael (25:17): “VeEilah Shenei Chayei Yishmael, Meiah Shanah, USheloshim Shanah, VeSheva Shanim,” “And these are the years of Yishmael, one hundred years and thirty years and seven years.” We know that Yishmael was evil for most of his life (although Chazal teach that he did Teshuvah near his death), so obviously we would not break down this Pasuk either.
Why, then, do we interpret the broken up Pasuk as meaning the person lived a perfect life only for Sarah?
The difference between Sarah, Avraham, and Yishmael is in the end of Sarah’s Pasuk., which adds, “Shenei Chayei Sarah.” It repeats, “This is the life of Sarah.” This is what tells us that the life of Sarah was perfect. We would not break down Avraham’s or Yishmael’s Pasuk because these words are not added for Yishmael or Avraham.
However, at this point we must go back and question Ramban. Is he saying that Yishmael and Avraham were equals?
One Midrash states that Avraham, like Sarah, was perfect, seeming to contradict Ramban. Additionally, as we learned before, we cannot say that Avraham was perfect, because the words Shenei Chayei Avraham do not appear! So how can this Midrash say Sarah and Avraham are equal?
Rav Moshe Sternbach offers an answer. He asks: If both Avraham and Sarah were perfect, why did Avraham live to 175 while Sarah died at 127? He suggests an answer based on a Midrash stating that both Rabi Yochanan and Rabi Chanina agreed that Avraham was 48 years old when he “came to life” and realized that there was a God. If we subtract 48 from 175 we get 127, meaning that for 127 years of Avraham life he was equal to Sarah in perfection and virtue. Hence, although he was not a Tzadik for his entire life, he could still be equated with Sarah to some extent.