The generations of Isaac. Moses returns to the main theme of his narrative, the history of the chosen people. Some events described in the succeeding verses occurred during the lifetime of Abraham. Since Abraham lived to be 175 years of age (Genesis 25:7), and was 100 at the birth of Isaac (Genesis 21:5), he must have been 160 years old at the birth of Esau and Jacob (Genesis 25:26), who were therefore 15 years old at his death. Ishmael’s death, at the age of 137 (v. 17), occurred much later, when Jacob and Esau were 63. Ishmael was 14 years older than Isaac (Genesis 16:16), and was therefore 74 years old when Isaac’s two sons were born. Chronologically out of place, the new section finds its logical place here in the narrative because it is Moses’ purpose to present Esau and Jacob’s life story without a break.