What is the definition of "Moras Ru'ach"?
Rashi (in Melachim 2, 14:26) #1: Pain (aggravation).
Rashi #2 and Targum Yonasan: A rebellious spirit (Refer to 26:35:2:1).
Targum Onkelos: Disobedience.
In what way were Eisav's wives a Moras Ru'ach to Yitzchak and Rivkah?
Rashi and Targum Yonasan: Besides worshipping idols, everything they did was with the specific intention of aggravating Yitzchak and Rivkah.
Ha'amek Davar: They were painful to each one in a different way. They knew that Yitzchak loved Eisav, so they were not afraid that he might become angry. Also, their idolatry pained him more than it pained Rivkah, who was used to it in her father's house. So, knowing that Rivkah did not hold of Eisav, they made it clear that they did not care about her.
Why did Yitzchak not rebuke Esav?
Seforno: Because he did not recognize the extent of Esav's evil. 1
Which explains why he set out to give him the Berachos, the cause of so much bitterness and hatred.
QUESTIONS ON RASHI
Rashi writes: "[The wives of Esav were a source of frustration] to Yitzchak and Rivkah" (Moras Ru'ach l'Yitzchak ul'Rivkah) - They would worship idols." How is this derived?
Gur Aryeh #1: The verse could have been phrased in the reverse, 'l'Yitzchak ul'Rivkah Moras Ru'ach,' thus equating the reactions of Yitzchak and Rivkah. Rather, it indicates that Yitzchak became upset first [which teaches that the frustration was due to Avodah Zarah]. 1
Gur Aryeh #2: Surely, their frustration was over outright deeds [that the wives committed], and idolatry is what the Canaanite locals were known for.
