With the marriage of Yitzchak and Rivkah, another link is forged in the chain that creates the people of Israel. Like Avraham and Sarah before them, they have difficulty conceiving:
And Yitzchak was forty years old when he took Rivkah, daughter of Betuel the Aramean of Paddan-Aram, sister of Lavan the Aramean, to himself as a wife. And Yitzchak entreated Hashem on behalf of his wife, because she was barren, and Hashem was moved, so his wife Rivkah conceived (Bereishit 25:20-21).

Radak says that Yitzchak prayed intensely so that he would not have to take a second wife as his father did.

And Hashem grants his prayer. Yitzchak and Rivkah are blessed with twins, Esav and Yaakov:
. . . . and Yitzchak was sixty years old when they were born (verse 26).
However, although the Torah clearly states how old Yitzchak was, it does not mention Rivkah’s age, neither here nor at any other milestone in her life.

How old was Rivkah?

We turn to the Oral Torah for answers. Most students of the Torah are familiar with Rashi’s calculation, based on midrashic sources, that Rivkah was three years old when she married Yitzchak. What is not as widely known is that there is another opinion found in the midrashim, and followed by some other commentaries that Rivkah was fourteen years old.

In examining these two views, we should not be influenced by contemporary conditions or attitudes, but by the evidence in the text of the Torah, and in the midrashim.

Here, then, are the facts: Avraham left Charan for the land of Canaan at the age of 75 (Bereishit 12:4) and he was 100 years of age at the time of Yitzchak’s birth (21:5). The account of the Akeidah (22:1-19) is followed by the report of Rivkah’s birth (verse 23), and then by Sarah’s death at age127 (23:1). Since Sarah was ten years younger than Avraham (17:17), this means that at the time of Sarah’s death, Avraham was 137 and Yitzchak was 37. As mentioned earlier, Yitzchak was married at 40 and became a father at 60.

Please note that there are certain traditions in the Oral Torah to which all midrashic authorities agree. The first concerns Avraham’s residences in Canaan. After traversing the land and descending to Egypt for a brief period, Avraham settles in Chevron (13:18) while still in his seventy-fifth year (Seder Olam, ch.1). He remains there until the cities of the plain are destroyed, when he is nearly 100, relocating in the south, the land of the Pelishtim (Bereishit 20:1). Thus, he lived in Chevron for 25 years. When, just before the Akeidah, the Torah says that Avraham resided
in the land of the Pelishtim for many years (21:34),
this means that he was there for a longer period than he had been in Chevron, namely, 26 years (Bereishit Rabbah 54:9). At the end of this time, Avraham is 126, Sarah is 116 and Yitzchak is 26.

The second point to which all midrashim agree is that the birth of Rivkah coincided with the Akeidah (Seder Olam, l.c.).

But, when was the Akeidah?

Bereishit Rabbah 56:11 has two versions regarding the age of Yitzchak at the time of the Akeidah. One version, which is adopted by Rashi, says he was 37. It is based on the opinion that Rivkah’s birth coincided with Sarah’s death, because
“before Hashem allows the sun of one righteous individual to set, He causes the sun of the next righteous individual to rise” (Bereishit Rabbah 58:2).
At the time of the Akeidah, therefore, Yitzchak would have been 37. Consequently, Rivkah at the time of her marriage to the 40 year-old Yitzchak was three years old.

This chronology helps to solve a problem. Based on Bereishit 16:3, and as explained in Yevamot 64a, a man who has not had a child with his wife for 10 years — as in the case of Avraham — may take a second wife. Yet, twenty years passed before Yitzchak implored Hashem to grant him and Rivkah children! However, if Rivkah was only 3 at the time of her marriage, the ten years until she was capable of bearing a child should not have been included.

All this, however, requires the addition of about 12 years, from the end of the period when Avraham lived in the land of the Pelishtim until the Akeidah. Rashi (on Bereishit 22:19) says that for those 12 years Avraham returned to Chevron.

There are two problems with this chronology, as pointed out by Tosafot on Yevamot 61b (“v’chen”). One is the fact that Rivkah, shortly before her marriage (Bereishit 24:16), is called NA’ARAH, which refers to a girl of at least 12 years of age!

The other problem is a midrash (Sifri Devarim 34:36) that states that Rivkah lived to the same age as Kehat, 133 years (see Shemot 6:18). This, say the Tosafists, represents a divergent midrashic tradition: As Rashi proves (on Bereishit 28:9 and 33:8), Yaakov received the blessing when he was 63, then spent 14 years studying with Ever, after which he worked for Lavan for 20 years and received word of his mother’s death two years later, for a total of 99 years. If Rivkah was 3 at the time of her marriage, then she was 23 when Yaakov was born, but that would make Rivkah only 122 at her death! Where are the missing 11 years?

The second version of Bereishit Rabbah 56:11 solves this. It says that Yitzchak was 26 at the Akeidah, at the end of Avraham’s residence in the land of the Pelishtim. It is this version which R. Eliyahu, the Gaon of Vilna, adopts. According to this chronology, Sarah did not die at the time of the Akeidah, because she was only 116. However, Rivkah was born then, so Rivkah was 14 when she married Yitzchak.

Yitzchak’s love for Rivkah was so deep that he allowed twenty years, rather than the permitted ten, to pass before praying for an end to her barrenness.

According to this time-line, Rivkah was 34 when Yaakov was born. When Yaakov received the blessing 63 years later, she was 97. Yaakov received word of her death 36 years later, when she was 133, as the Sifri cited above stated.

As our Sages say (Bamidbar Rabbah 13), “There are seventy facets to the Torah.”