Jasidut sobre Génesis 25:19

And these are the generations of Yitzchak, the son of Avraham etc (Gen. 25:19) We need to explain the explanation of Rashi z"l "Yaakov and Esav that are spoken about in the portion" through the way of hint [remez]. Yitzchak is a hint to Judgment [Din], and Avraham is a hint to Lovingkindness [Chesed] as known. And there are tzadikim whose beginning is suffering and whose end is serenity, and there are evil people who are the opposite, and this is "these are the generations of Yitzchak the son of Avraham", meaning, after Judgment, Lovingkindness is born. And "Avraham gave birth to Yitzchak" means that after Lovingkindness, Judgment is born. And the explanation of Rashi z"l (Rashi on Genesis 25:19:1) that these are Yaakov and Esav who are talked about in the portion is to explain this hint that runs throughout the portion, regarding Yaakov and Esav, that is, Yaakov's beginning is Judgement and his end is serenity, as explained, and regarding Esav it is the opposite.

Genesis ‎25,19 “And these are the generations of Yitzchok, the son ‎of Avraham; Avraham begot Yitzchok.” (We have been told in ‎Genesis 21,12 ‎כי ביצחק יקרא לך זרע‎, “for your seed (descendants) ‎will be known through Yitzchok.” G’d told Avraham already ‎before Yitzchok was born that although he had another son, ‎Yishmael, his descendants would always be associated with ‎Yitzchok. It was understood that this promise was contingent on ‎Yitzchok becoming a righteous person, a tzaddik, future ‎generations would not trace themselves back to their ancestor ‎Avraham but each generation would only trace itself back to their ‎immediate forbears, i.e. their fathers. In other words, the new ‎element provided by our verse above is that even Yitzchok’s ‎offspring would trace themselves back to their founding patriarch ‎Avraham. We learn from here also that it is up to the “son” to ‎demonstrate by his deeds that he was not only descended from ‎his father but could claim previous generations as his “roots.” ‎When we consider this, the word ‎תולדה‎ is no longer an adjective, ‎an attribute of a person which he came by naturally, without any ‎input of his own, but it is a tribute to the person so described, ‎meaning that he is a worthy descendant of his illustrious forbears.‎

Or say , also, through the way [of interpreting] of remez (hint): behold, we see the deeds of people - evil people doing evil, the incitement of the evil impulse in them begins with saying to them that it is a mitzvah to do this, when in truth it is a transgression. And the tzadikim who safeguard themselves from transgressions sometimes will do a transgression for its own sake [lishmah], as we find 'it is permissible to lie [lit. change] for the sake of peace' (Bava Metzia 24a, Tosafot on Bava Metzia 24a:1:1, see also Yevamot 65b) - and this is "these are the generations of Yitzchak"(Gen. 25:19), meaning, the judgment that comes through transgressions. The reason of the transgression is because "son of Avraham" is a hint to a mitzvah, that is, that the yetzer hara says to him that this is a mitzvah, and there are tzadikim who do a  transgression for its own sake, as explained. And this is hinted in "Avraham begot Yitzchak", meaning, a great tzadik sometimes begets "Yitzchak", that is, Judgment, by sometimes doing a transgression for its own sake because of the tzadik's great righteousness. And this is easy to understand.