21 But My covenant I will maintain with Yitzchak, whom Sara shall bear to you at this season next year.”
17:21 But My covenant I will maintain with Yitzchak
Avraham was chosen to be God’s emissary in this world, to live in the Land of Israel, and to establish a nation with a unique mission. But who would be Avraham’s heir, Ishmael or Yitzchak? This ambiguity is eliminated when Hashem declares that, although a great nation will emerge from Ishmael’s lineage, Yitzchak is the chosen heir to Avraham’s legacy and Eretz Yisrael.