Seder 25: A Chronological Question in Genesis 27

 As Gen 27 opens, we read that  "Isaac was old and his eyes were dim so that he could not see."  How old was Isaac at this point?

From numbers given later in the book of Genesis, it appears that Isaac's son Jacob was 77 when he left home in Gen 28.  Since Isaac was 60 when Jacob was born (Gen 25:26), Isaac was no older than 137 when he blessed Jacob in Gen 27.  Although Isaac talked in Gen 27:1-4 as if he were on his deathbed, he lived another 43 years after that to die at the ripe old age of 180.

So what prompted Isaac to impart his blessing at that particular time?   The text of Genesis does not say, but the age 137 will ring a bell for careful readers of Genesis.  Isaac's father Abraham was 137 when his mother Sarah died at age 127 (Gen 23:1).  Also, Isaac's brother Ishmael was 137 at his death (Gen 25:17).  So perhaps Isaac was thinking of these previous events when he reached age 137.  He may have been feeling old because Ishmael had died at that age.  

Some Jewish commentators wondered if perhaps Isaac was feeling old because Ishmael had just died.  They reckoned Ishmael was 14 years older than Isaac, so there is a tradition that Isaac was only 123 when he blessed Jacob.  That tradition raised a question:  If that was the case, what did Jacob do for 14 years after receiving his blessing and before leaving home?

The traditional answer is that Jacob studied for 14 years at the school originally founded by Shem and later carried on by Shem's descendant Eber.  The Bible says nothing about such a school, but there are legends about Abraham and Isaac having studied there.  In Jewish tradition this hypothetical school is pressed into service to provide answers to certain perplexing questions raised by details in Genesis.  

One such question was about the identity of Melchizedek.  A tradition arose that Melchizedek was actually Shem, and one reason Abraham respected him was that he had studied under him.  

Another question was about what Isaac might have done right after the events of Gen 22, since Isaac isn't mentioned returning from Mt Moriah with Abraham in Gen 22:19.  Perhaps he spent some time at the school of Shem and Eber.

A third question involves the means by which Rebekah "inquired of God" during her troubling pregnancy (Gen 25:22).  That kind of language is usually used in the Bible when a person seeks answers from some authorized representative of God----e.g., a priest.   But what representatives of God were around then?  Perhaps Rebekah consulted with a descendant of Shem.  

There is a further tradition that during her pregnancy, Jacob would kick whenever she passed this school, while Esau would kick whenever she passed a pagan temple.  This tradition is an example of attempts to provide a rationale for the fact that the futures of Jacob and Esau seem to have been to some extent predetermined (Gen 25:23).