Sarah bears Yitzchak at ninety, Avraham circumcises him at a hundred, and the joy lasts exactly until the weaning feast, when Sarah demands that Hagar the Egyptian maidservant and her son Yishmael be sent away. The analysis argues that the chapter decides nothing by lineage and everything by what a person is doing at the moment. Two words carry the case. Sarah's grounds are compressed into the single participle metzachek — playing, mocking, making sport — and the traditional reading fills it with present offenses rather than genealogical unfitness; God confirms this by calling Yishmael Avraham's own seed and promising him a nation even while endorsing his removal from the covenant. Then the criterion reverses. When the water runs out in the wilderness, God hears the boy ba'asher hu sham, "where he is": judged by his present deeds, not by what his descendants will become. The frame supports the reading. The chapter opens just after Avraham prays for the barren household of Avimelech, a foreign king, and closes with Avraham planting a tamarisk at Be'er Sheva and bringing strangers to bless God there. Read on the first day of Rosh Hashanah, the chapter insists that election is not immunity and exclusion is not abandonment.
In the haftarah, the opening of the book of Shmuel, the childless Hannah prays at Shiloh, where the Mishkan then stood, moving her lips without sound; Eli the kohen mistakes her for a drunkard. From those silent words the sages derived the laws of prayer, and from her vow came the prophet Shmuel.