Musar su Genesi 21:12

The sixth quality: The pious man will not put any personal matter ahead of his service to God, until he has first fulfilled the commandment of his Creator, blessed be He. For we find that in any matter which the Creator, blessed be He, commanded Abraham, Abraham did not perform any one of his personal acts before fulfilling the commandment of God, blessed be He. Thus, in the covenant of circumcision, it is said (Genesis 17:22), “And God went up from Abraham.” And it is further written (ibid., 17:26), “In the selfsame day was Abraham circumcised,” and he did not perform any personal act until he had fulfilled the commandment. It is said in the case of Ishmael (ibid., 21:12), “In all that Sarah saith unto thee, hearken unto her voice, for in Isaac shall seed be called to thee.” It is written immediately after this (ibid., 21:14), “And Abraham arose up early in the morning, and took bread and a bottle of water, and gave it unto Hagar, putting in on her shoulder, and the child, and sent her away.” We learn from this that in the dream of the night it was told to him, and therefore, he rose early in the morning before doing any other deed in order to fulfill the command of God, blessed be He.

Jacob was the descendant of Isaac and Rebeccah. In the case of Abraham's son Isaac, G–d had promised Abraham only כי ביצחק יקרא לך זרע, that part of Isaac would be his worthy seed, not all of Isaac. The Torah reports that Rebeccah loved Jacob (25,28). We have said that then the world was filled with Jacob's "beauty," which was of the kind once possessed by Adam, מטתו שלמה, Jacob's bed was perfect, i.e. all his children were loyal to his teachings which enabled him to become known as ישראל. Since only ישראל is called אדם, the connection between Jacob and Adam is clear.

And then there is one who listens and is rewarded. That would be Abraham, our father for it was said to him "in all that Sarah saith unto thee, hearken unto her voice" (Gen. 21:12). And what was his reward? "For in Isaac shall thy seed be called" (Gen. 21:12).