Exploring Isaac's Story

Isaac ruled over his father's territory in ancient Edom. 

The territory extended between Hebron and Beersheba, both shown on this map.

Alice C. Linsley

Now Isaac sowed in that land and reaped in the same year a hundredfold. And the LORD blessed him, and the man became rich, and continued to grow richer until he became very wealthy; for he had possessions of flocks and herds and a great household, so that the Philistines envied him. (Gen. 26:12-14)

Isaac was a high-ranking prince of ancient Edom. His name is derived from iššakkum, a Sumerian title designating the ruler or prince. He was a man of great wealth.

He was Abraham's proper heir, and he inherited control of Abraham's territory that extended north-south from Hebron to Beersheba. That territory was entirely in the region that the Bible calls "Edom" or "Idumea" in Greek. Edom was under the control of Horite Hebrew ruler-priests listed in Genesis 36. 

Both Hebron (where Sarah lived) and Beersheba (where Keturah lived) were in ancient Edom. Abraham's territory extended between the settlements of his two wives and included mountains and lowlands.

Questioning Isaac's existence

When I was in seminary, my Old Testament professor told the class that he doubted Isaac’s existence because there is so little information about Isaac. He noted that the story of Isaac pretending that Rebecca was his sister parallels the story of Abraham asking Sarah to say that she is his sister. He concluded that Isaac is a literary construction reflecting the author’s love of doublets, two different narrative accounts of the same event.

Duplicative narratives reflect a pattern that is familiar to two different authors. An example is the attempt of Abraham and Isaac to pass off their wives as their sisters. In Abraham's case, Sarah was indeed his half-sister. They had the same father, but different mothers because it was the custom of high-ranking Hebrew ruler-priests to have two wives. It is likely that Issac followed the marriage pattern of his Hebrew ancestors. If so, his first wife was a half-sister, the daughter of Abraham and Keturah. 

Another example of a duplicative pattern involves the birth of twins. There are close parallels between the birth of Esau and Jacob and the later birth of Zerah and Perez. Both stories speak of the birth order of twins and identify the firstborn sons as Esau and Zerah. By rights, Esau was Isaac's proper heir, but as such, he probably was not Rebekah's son. He would be the son of Isaac's half-sister, the bride of his youth. In the Hebrew marriage and ascendancy, the firstborn of cousin brides did not rule over the territories of their fathers. They were sent to serve their maternal grandfathers, which is what happened with Jacob. 

My professor also noted the limited genealogical information about Isaac. However, a closer look reveals that Isaac had at least 7 half-siblings. They include Ishmael (born of Hagar) and Eliezer (born of Mesek). Hagar and Mesek were concubines. Genesis 25:6 makes it clear that Abraham had more than one concubine. The Hebrew literally speaks of Abraham's sons by concubines (Speiser on Genesis, Anchor Bible, p. 197).

Abraham's cousin wife Keturah bore him 6 sons: Joktan/Jokshan, Medan, Midian, Zimran, Shua, and Ishbak/Yishbak. Yishbak means "sent away". He is one of the sons to whom Abraham gave gifts and sent away from Isaac. The sending away of non-ascendant sons is made explicit in Genesis 25:5-6: “But Abraham gave everything he possessed to Isaac. While he was still living, he gave gifts to the sons he had by his concubines, but then sent them away to the country of the east, putting a good distance between them and his son Isaac.”

Ishmael also was a sent-away son. The circumstances of his being sent away vary in the book of Genesis. According to one account, Ishmael and Hagar were sent away ("cast out") because of Sarah's jealousy (Gen. 21:10). According to another account, Abraham's eight sons were given gifts and sent away from Isaac's territory before Abraham died.

While I appreciate my professor’s observations, I disagree with his conclusion. Isaac’s historicity can be verified by his adherence to the kinship pattern of his ancestors. Fictional characters do not have verifiable kinship patterns.

The Bible does not identify Isaac’s first wife. Her presence is suggested through multiple lines of evidence. The text in Genesis 26:7 speaks of Isaac having a sister wife. The half-sister wife clearly was not Rebekah since she was Isaac's patrilineal cousin. Isaac would have married according to the pattern of his Hebrew ancestors which means he had two wives. Isaac was living near Beersheba when Abraham’s servant arrived from Padan-Aram with Rebekah. Beersheba was where Keturah resided and where Isaac's half-sister bride was living.

The twin boys assigned to Rebekah were probably the firstborn sons of Isaac’s two wives. Since Esau was Isaac’s proper heir, he would have been the firstborn son of Isaac and his first wife, his half-sister. Rebekah would be the mother of Jacob, a son sent to serve in his maternal grandfather’s territory. This aligns with the social structure of the early Hebrew, as the son of the cousin bride belonged to the household of his maternal grandfather and would reside there after coming of age. This occurred with Jacob who went to live with his maternal uncle (avuncular residence).

Related reading: Abraham's Sons; Abraham's Two Concubines; Sent-Away Sons; The Marriage and Ascendancy Pattern of Abraham's People; The Hebrew Hierarchy of Sons; Royal Sons and Their Maternal Uncles; Hebrew Rulers with Two Wives