Sarah's lifespan was part of an elaborate numerology hidden in the story of the patriarchs. True, her age when she gave birth (90) might have inspired awe among the earliest audience of this story, as would that of Abraham (100) but these numbers were probably chosen mainly because they were easy for tradents to remember as they passed the stories down orally to the next generation.
Sarah's lifespan of 127 years fits into the formula for the three patriarchs, but at a secondary level:
- Abraham lived to 175 (5 X 5 X 7)
- Isaac lived to 180 (6 X 6 X 5)
- Jacob lived to 147 (7 X 7 X 3
- The lifespan of each patriarch involves a perfect square (5, 6, then 7 in a numeric
- the third factor also forms a series (7, 5, 3)
- in each case the sum of the factors is 17.
Furthering the above formulas, Sarah lived to 127 years, which is the sum of these consecutive square numbers plus 17 (127 = 5 squared + 6 squared + 7 squared + 17). The early Hebrews found the number 17 to have mythic significance. Of all the people in the Book of Genesis, they saw the patriarchs as most important, and Sarah was the supreme matriarch.