“And G-d said to [Rivkah]” (B’reishis 25:23). Although these words would seem to indicate that there was a direct communication from G-d to Rivkah, Rashi, based on B’reishis Rabbah 63:7, tells us that the message was given to Rivkah through Shem (Noach’s son). However, later in our Parasha, G-d did communicate directly with Rivkah. When Rivkah “heard” Yitzchok tell Eisav to hunt food for him so that he could bestow a blessing upon him (27:5-7), although she might have (over)heard this directly, Midrash Tanchuma (10) and Targum Yonasan tell us that she heard it through the “Divine Spirit,” the same expression used by Rashi for how G-d communicated with Shem to give Rivkah her answer. After the blessing was given to Yaakov instead of Eisav, and Eisav planned on killing Yaakov (27:41), Eisav’s “thoughts” were “told” to Rivkah by the “Divine Spirit” (27:42, see Rashi and Targum Yonasan). Why did Rivkah need to go to Shem to find out from G-d what was going on with her pregnancy if she was also worthy of receiving divine communication?
Mizrachi (25:23) says that Rivkah had to go to Shem to find out why she was in such distress because she was not a prophetess, as evidenced by Rivkah not being one of the seven prophetesses listed in the Talmud (Megilla 14a). Which makes Rashi saying that Rivkah knew what Eisav was thinking through the “Divine Spirit” even more puzzling. Nevertheless, when Rashi (29:34, see B’reishis Rabbah 67:9 and 72:6) says that all of our foremothers were prophetesses, Mizrachi (on 29:34), in order to defend his opinion here, says that this is a matter of dispute between sources, with Rashi following one opinion here (25:23) and the other opinion there (29:34). Putting aside the discussion about whether Rashi quotes conflicting opinions on different verses, since Mizrach is clearly of the opinion that he does, Rashi’s comments on 27:42 could also be following the opinion that all of our foremothers, including Rivkah, were prophetesses, while his comments here follow the opinion that the only foremother who was a prophetess was Sara.
B’er Hatorah (27:42) gives a different answer, suggesting that when Rashi says Rivkah “heard” through the “Divine Spirit” he wasn’t referring to prophesy, but to her wisdom, which is a gift from G-d, as she figured out (from other clues) that Eisav’s intent was to kill Yaakov. [The notion that this could be described as being “told” to Rivkah by G-d even though there was no communication is not that different from when Avraham was “told” that Rivkah was born (22:20-23), with Rashi telling us that it was G-d who had informed him that Yitzchok’s mate had been born because Avraham was concerned about Yitzchok getting married. If G-d told Avraham not to worry about who Yitzchok will marry because Rivkah, his future spouse, had just been born, the whole mission of his servant, including (and especially) his not knowing who he was looking for, seems rather superfluous — unless Avraham put Eliezer through the whole ordeal because he knew that “finding” Rivkah miraculously would impress Rivkah’s family much more than knocking on their door and saying “I’m here to take Rivkah to Canaan to marry Yitzchok because G-d told Avraham that they were meant for each other.” If, on the other hand, as Eitz Yosef suggests (in his commentary on B’reishis Rabbah 57:3), Avraham being “told” by others that his brother Nachor’s family had grown made him realize that a potential spouse for Yitzchok could be in Charan (see Eitz Yosef on 57:1), and this can be equated with G-d “telling” him that Yitzchok’s mate had been born (since G-d had caused this information to become known to Avraham at that point in time specifically to ease his concerns about finding a wife for Yitzchok), Eliezer’s trip to Charan without knowing the ending makes sense. Similarly, Rivkah being made aware of other comments of Eisav (or other actions) that led her to conclude that he wanted to kill Yaakov, which caused her to send him away, could be attributed to G-d and His “Divine Spirit” without Rivkah being a prophetess.] It is worth noting, though, that the same expression, “Divine Spirit” (“Ruach haKodesh”) is used by Rashi to describe how Shem knew why Rivkah was in distress, and the information he relayed — that she is carrying two nations, who would constantly be at war with each other, with the younger ultimately coming out on top — is too specific for Shem to have just figured it out based on his wisdom.
Another point worth noting is that just as Rivkah was not included in the Talmud’s list of prophetesses, Shem is not listed in Rashi’s list of the 48 prophets the Talmud alluded to. [Even though Nachalas Yaakov, on 25:23, suggests that Shem and Ever are the two whom Rashi was unsure were included in the 48 prophets, Rashi does not list them, and if he thought Shem was one of the 48, he would have said so.] Therefore, Rivkah not being able to answer her own query because she was not one of the seven prophetesses should apply to Shem too, and should have prevented him from being able to give her an answer as well, at least according to Mizrachi’s formulation. Which brings us back to the question of why Rivkah had to go to Shem in the first place if she was a conduit for “Ruach haKodesh” herself, and also leaves us wondering how Shem was able to provide the answer if he wasn’t one of the 48 prophets, as well as how to reconcile the Midrash that says our foremothers were all prophetesses with the Talmud, which only includes Sara in its list.
Rinas Yitzchok (II, on 27:13) references Nedarim 38a, which lists the qualifications necessary for prophecy, and the Rosh’s commentary there (see Kesef Mishneh on Rambam’s Hilchos Y’soday Hatorah 7:1), that these qualifications are only necessary for those who receive prophecy on a regular basis, but not for those who receive occasional prophecy. He therefore suggests that Rivkah did receive occasional prophecy (including what Eisav’s intentions were), but did not qualify as a “permanent” prophetesses, and therefore wasn’t included in the Talmud’s list (which is only those who received prophecy on a regular basis). This would also explain why Rivkah went to Shem, as this wasn’t one of the occasions where she received prophecy. The Midrash could be referring to the fact that all four foremothers received prophecy at least occasionally, while the Talmud lists only Sara because she was the only one of the four who did so regularly. And even if Shem didn’t receive prophecy on a regular basis, we don’t know if Rivkah knew that, and if she did, she still could have hoped that this was one of the occasions when he would receive prophecy (and it was).
A similar possibility is based on the Talmud’s answer as to why it didn’t include more prophets on its list despite there being more than only 48; it only included those whose prophecy was needed for future generations. If Rivkah’s prophecy (that she knew that Eisav wanted to kill Yaakov) wasn’t needed by future generations, she wouldn’t have been included in the Talmud’s list. Although this doesn’t address all the issues raised above, there might be other reasons why, even if Rivka was a prophetess, she had to go to Shem for help regarding her troublesome pregnancy.
First of all, there is a Talmudic concept of “a prisoner not being able to free himself from prison” even if he can help others get out (B’rachos 5b), meaning that even if Rivkah had the ability to help others in distress via her ability to receive prophecy, she may not have been able to help herself. Additionally, “the Divine Presence does not rest [on a person] in sadness” (Shabbos 30b), which is why Elisha needed a musician to play for him before he received prophecy (M’lachim II 3:15). Therefore, even if Rivkah was normally able to receive prophecy, while she was in distress she could not, and had to reach out to Shem. And, there was a long period of time between the two episodes. Yaakov was blessed by Yitzchok when he was 63 years old (see Rashi on 28:9), which was when Rivka heard through Ruach haKodesh that Eisav wanted to kill him. Since she was pregnant with Eisav and Yaakov when she went to Shem, at least 63 years had passed from the time that Rivkah had to rely on Shem’s Ruach haKodesh until she relied on her own to be “told” about Eisav’s intentions. For all we know, at the time of her pregnancy (which was before she was a “foremother”) she wasn’t yet on the level of receiving prophecy. As she continuously grew in her spirituality, though, she attained that level, and became a prophetess.