“Sarah’s lifetime was one hundred years, twenty years, and seven years–the years of Sarah’s life.” (23:1)
Rashi z”l comments: “The word ‘years’ is repeated to indicate that they were all equally good.”
R’ Yitzchak Klein z”l, Hy”d (rabbi of Kosice, Slovakia; killed in the Holocaust) writes:
“Our Matriarch Sarah experienced many ups and downs in her life, and she knew times of suffering. Nevertheless, all of her days were equally good. How so?”
He explains: The Gemara (Berachot 57b) relates about Rabbi Chanina ben Dosa: “Hashem says, ‘The entire world is sustained in the merit of My son Chanina, and My son Chanina is satisfied with a measure of carobs from Erev Shabbat to Erev Shabbat’.”
Because a Tzaddik is satisfied with little and he does not take more from this world than is necessary to sustain himself, his merit remains for others, who are then sustained in the merit of the Tzaddik’s Mitzvot.
This is the meaning of the verse (Mishlei 13:25), “A righteous person eats to satisfy his soul, and the stomach of the wicked will lack.” If the Tzaddik eats to satisfy all his desires, then the wicked will go hungry, for no merit will remain to sustain them.
In the same vein, Sarah considered all of her days to be equally good, despite what we would view as negative experiences, because she knew that her suffering would provide merit to those who had no merit of their own, and her merit would protect them.
Therefore, in connection with our verse, a Midrash cites the verse (Tehilim 37:18), “Hashem knows the days of the perfect”–i.e., Hashem loves the days of the perfect, for all their days are equal. “Good” and “bad” are considered good because, when Tzaddikim forego living off of, and using up, their own merits, those merits remain as an inheritance for others. (Birkat Avraham)
“Va’yihyu chayei Sarah” / “Sarah’s lifetime was one hundred years, twenty years, and seven years . . .” (23:1)
R’ Yehoshua ibn Shuiv z”l (Spain; early 14th century) observes: Sarah lived for 37 years after Yitzchak was born, and these were no doubt the happiest years of her life.
This is alluded to in the verse: “Va’yihyu chayei Sarah,” which could be translated: “Sarah’s lifetime was ‘va’yihyu’.” The gematria of the word “Va’yihyu” (vav-yud-heh-yud-vav) is 37, alluding to the prime years of Sarah’s life. (Derashot R’ Yehoshua ibn Shuiv)
And Abraham said to Eliezer, the eldest servant of his house who ruled over all he had... "Promise that you will not take a wife for my son from the daughters of Canaan." (24:2)
Eliezer's position and importance in Abraham's household is recorded for an important reason. When it came to financial matters, Abraham trusted many people. But when it came to spiritual matters, such as choosing a wife for his righteous son Isaac, Abraham would only send his most faithful servant, and even then Abraham made Eliezer promise to follow his instructions. (Yalkut Hadrush)
Reprinted from the email of R’ Yedidye Hirtenfeld’s Chaye Soro 5785 parsha sheet whY I Matter for the Young Israel of Midwood