The Women’s Error:
The Sanzer Rov zy”a (Divrei Dovid-Karshinov, page 21) said the following in the name of the Magid of Kozhnitz zy”a: “Whenever women mix in, there is agmas nefesh (anguish).” He brought proof to this statement from Rivkah Imeinu. When Yitzchok wanted to bless Esav, Rivkah mixed in and arranged for Yaakov to get the blessings. This caused Esav to hate Yaakov. If she had not done this, Esav may have received the brachos but he would have had no benefit from them as Yitzchok said that when the receiver of the blessings falls – meaning that he does not keep the Torah – his yoke would be removed. And would Esav keep the Torah? Therefore, even if Esav had received the blessings, he would not have benefited from them and they would have gone over to Yaakov.
“Yesterday, when you told me the man’s name, he was in the middle of lighting the menorah and as a result of this mitzvah, his neshama was shining!” Accordingly, when Esav was with his father and was doing the mitzvah of kibud av, his neshama was bright, which is why Yitzchok loved him. This time, however, he was not doing the mitzvah of kibud av, as he only was thinking about himself, so his neshama was not illuminated. Thus, Yitzchok was able to see who he really was.
וְהָיָה כַּאֲשֶׁר תָּרִ יד וּפָרַ קְתָּ עֻלּוֹ מֵעַל צַוָּארֶ ךָ (כז, מ)
And it will be when he falls that you will break his yoke off your neck. (27:40)
