The literary division of Genesis along the lines of generations (Heb. toledot) goes from 25:19 until the end of ch. 35, but narratively the focus shifts at 28:10 from Isaac and his immediate family to his son Jacob in particular.  In the Genesis narrative, the account of Jacob provides the pivotal connection between the patriarchal period and the Exodus generation, since it is with Jacob that the people of God go from being just a family to being a nation.  It was Jacob’s family that would go into Egypt during the famine; it would be the nation of Israel that would come out in the Exodus.  Nevertheless, although Genesis gives greater attention to Jacob—almost half of the book—the short account of Isaac is still important in showing how God’s covenant promises were conveyed to Jacob.  Three themes related to the covenant can be discerned in chapters 23 to 28: (1) How God protected the promised seed of Abraham; (2) The continual need for covenantal love to the LORD, shown negatively by the failures of His people; (3) How God extended and confirmed His covenantal promises to His people nonetheless.

The continuation and protection of the chosen seed.  Much of the Abrahamic narrative is focused on the coming of an heir through whom God’s covenant promises would be conveyed, and that heir was Isaac.  Once Isaac was born and especially in his brush with almost being sacrificed, God’s protecting hand remained upon him.  That protection continued in his life and conveyed to his son Jacob.  The godly seed risked being lost because of intermarriage with the pagan nations amongst whom Isaac and his family lived.  Abraham probably recognized this, which was why he was adamant that his son neither marry into the Canaanites nor return to the land of Haran which Abraham left.  The beautiful account in Genesis ch. 24 of Abraham’s servant finding Rebekah, a wife for Isaac, shows God’s providential working through the entire episode.  Rebekah, like Sarah before her, was barren until the LORD opened her womb with twins.  The sovereignty of the LORD was evident in His revelation that the older child would serve the younger (25:23), a pattern that God would follow repeatedly throughout the remainder of biblical history.  God intervened when Isaac was in Gerar, to prevent another Abimelech from taking Rebekah into his harem given that Isaac followed his father’s sinful pattern of declaring her to be his sister, not his wife (26:6-11).  The risk to the godly line was highlighted in the narrative by the negative example of Esau (26:34-35).  Esau’s direct threat to Jacob, through whom God’s promise would come, was thwarted by Rebekah’s justification desire that Jacob not succumb to marrying women of the land but to find a wife from among her own family (27:46-28:5).

The continuing need for covenantal faithfulness.  Isaac and his family, like Abraham, had to learn covenantal faithfulness.  Despite God’s deliverances of Isaac, Isaac still trusted in his own connivance when he was in Gerar, rather than in the protection of the LORD (26:9).  Moreover, even though Rebekah had been told that of her sons, the older would serve the younger, Isaac favored Esau over Jacob for little more than personal reasons (25:27-28).  Esau, in fact, was indifferent to the covenant promises of God, as evident in how he despised his birthright (25:29-34).  Rebekah and Jacob were not much better than Isaac, in that while they did value the promises of God, they sought to attain those promises through their own efforts, rather than in trusting in God.  This is clearly displayed in the deception that they exercise toward Isaac to secure his patriarchal blessing for Jacob (27:1-29).  Jacob, in his experience of fleeing to and then twenty years later returning from Padan Aram would be the only one who would develop the kind of covenantal faithfulness that his grandfather Abraham exhibited, as would be seen in subsequent chapters.

The extension and confirmation of God’s promises.  Despite this lack of covenantal loyalty, within these chapters one sees the echoes of God’s covenant promise is in the blessing that Rebekah’s family gave her as she left to become Isaac’s wife (24:60).  The LORD extends the covenant promise to Isaac during a famine, when he tells Isaac to stay in the land despite the famine, and that in so doing and in keeping God’s statutes and laws as Abraham had done, He would multiply Isaac’s offspring and bless the nations of the world through him (26:1-5).  This harkens back to God’s original promise to Abraham in 12:1-3.  The most obvious extension of God’s promises is in Jacob’s acquisition of the birthright of the firstborn (25:29-34) and then in Isaac’s subsequent blessing upon Jacob (27:27-29).  The writer of the epistle of the Hebrews points to this sole act as the justification for including Isaac in the testimonies of faith (Heb. 11:20).  Less obvious but also important are certain acts that help secure the patriarch’s legal claims to the land.  This is the significance of the covenants Abraham and Isaac made with the Abimelechs (21:22-34 and 26:12-33), as well as the extensive discussion of why Abraham bought the land from Ephron the Hittite to bury Sarah (ch. 23).  These transactions established a legal basis for Abraham and Isaac to the land, and such legal recognition was an indirect confirmation that God’s promise to give Abraham’s offspring would be fulfilled.