141) “And, behold, Sarah your wife shall have a son.” It does not say, “You will have a son,” so he would not think that it would be from Hagar, as in the beginning. It is written, “A son honors his father, and a servant his master.” “A son honors his father” is Isaac with respect to Abraham.
142) He honored him when he tied him at the altar and wished to offer him as sacrifice. Isaac was thirty-seven years old at the time, and Abraham was old. If he kicked him with one leg, he would not be able to stand against him. But he respected his father, and his father tied him like a sheep while he did not resist him so as to do his father’s will.
143) “And a servant [honors] his master” is Eliezer with respect to Abraham. When he sent Eliezer to Haran and did there all that Abraham wished, he honored him, as it is written, “And the Lord has blessed my master.” And it is written, “And he said, ‘I am Abraham's servant,’” to honor Abraham.
144) Indeed, a man who brings silver and gold and gems and camels, and who is respectable and handsome, did not say that he was loved by Abraham or that he was his kin. Rather, he said, “I am Abraham's servant,” to raise Abraham's merit and honor in their eyes.
145) This is why it is written, “A son honors his father, and a servant his master.” And you, Israel, My sons, it is a disgrace for you to say that I am your father or that you are My servants. “If I am a father, where is My honor?” This is why it is written, “And, behold … a son.” This is certainly a son, and not Ishmael. It is a son who honors his father properly.
146) “And, behold, Sarah your wife shall have a son.” A son for Sarah, since she died for him because she heard of his tying. And for him, her soul ached until she bore him. “And, behold, Sarah … shall have a son,” to rise for him while the Creator is judging the world, since then it is written, “And the Lord visited Sarah,” for Isaac was born in the beginning of the year. Thus, He remembered Sarah because of Isaac, which is why he is a son to Sarah. “And behold, Sarah … shall have a son,” since the female takes the son from the male. It follows that the son is with the female; this is why he says, “And behold, Sarah … shall have a son.”
147) “And Sarah was listening at the tent door behind it.” “And Sarah was listening” to what he said at the tent door, which is the bottom degree, the door to faith, the Shechina. It is written, “And he was behind it,” meaning that the upper degree, the Creator, thanked him, for since the day that Sarah was in the world, she did not hear a thing from the Creator except at that time.
148) Sarah was sitting at the tent door to hear what was being said, and she heard this news that Abraham was given. This is why it says, “And Sarah heard in the tent door.” “And he was behind him,” meaning that Abraham was sitting behind the Shechina.
149) “Now Abraham and Sarah were old, advanced in days.” “Advanced in days” means that at that time, they came to the measure of days to which they were worthy—a hundred years for the one, and ninety years for the other. “Advanced in days,” since the day ended, evening was approaching because it was completed. Here, too, “advanced in days” means that their days have been completed.
150) And at that time, Sarah saw herself in another pleasure, for the manner of women had returned to her. This is why she said, “And my lord being old,” for he is unfit for begetting because he is old. And she did not say about herself, “For I am old.”