Kommentar zu Bereschit 25:5

AND ויתן אברהם וגו AND ABRAHAM GAVE etc. — R. Nehemiah said, he gave him the blessing as a legacy (literally, will, testament). The Holy One, blessed be He, had said to Abraham (12:2) “Be thou a blessing” which means “the blessing are entrusted to you that you may bless whomsoever you please”, and Abraham transferred them to Isaac (cf. Genesis Rabbah 61:6).

ויתן אברהם את כל אשר לו ליצחק, “Avraham deeded all that was his to Yitzchok. Some people question this procedure, basing themselves on Ketuvot 53 where the Talmud rules that a father must not re-allocate part of his estate from a son who is morally unfit to one who has developed morally and ethically to his liking, seeing he does not know how the grandson from either son will turn out. It is stated there that a convert the son of Hagar, i.e. a slave woman, cannot inherit at any rate, as whatever is his belongs to his master. Whereas this is a good answer concerning the status of Yishmael, it leaves unanswered the question how Avraham could disinherit the sons of Keturah. I believe that there is no difficulty at all, seeing the Torah had told Avraham specifically that his seed will only be known through Yitzchok, i.e. that Yitzchok will be his only heir. It does not mean that the other sons were intrinsically unfit because of their character or some other impediment, According to Rashi, quoting Sanhedrin 91, Avraham handed to these sons שם טומאה, i.e. seeing they referred to their idols by the sacred name of the Creator, he taught them to refer to these idols by some other name. It is also possible that the meaning of this strange sounding comment by the Talmud is that he informed them of a name for G’d which it is permissible to use even in their state of ritual impurity. All this, because he observed that these sons of Keturah were practicing different forms of idolatry and worshipping those idols. The reason that these sons of Avraham also practiced this form of idolatry was their being so anxious to obtain information about their impending fate, something which the religion of their time promised to have for those who practiced their cults. By informing them of this name for the true G’d, he told them that by invoking it they would become privy to knowledge of the future. [According to the Maharal from Prague the reason Avraham taught his sons the “names” of these idolatries, i.e. the essence of their teachings, was to enable them to counter the damaging influence the power of these demons exercised upon them. According to the author of the כתב והקבלה, Rabbi Mecklenburg, the מתנות, “gifts” Avraham gave to his sons was the know how to protect themselves against the insidious influence of the various religious cults prevalent in their neighborhood.. Ed.]

He gave him ברכת דייתיקי. [According to the first approach, ברכת דייתיקי means “the blessing of Hashem,” and] Rashi is answering the question: Did not Avraham already give Yitzchok all he had (see Rashi on 24:10)? The word דייתיקי comes from עתיק יומין, which means “Hashem.” Alternatively, דייתיקי comprises three words, דאי תהא קאי, and means, “the gift will be established.” In other words, Avraham now gave Yitzchok active possession of the property he had previously granted him.