In Genesis 22A, Pastor Armstrong says that Issac was in his late 20s to 30s when Abraham attempted to sacrifice him. I’d always thought he was a boy around 13 or so. What biblical evidence is there for this older age?
The Bible does not tell us Isaac’s exact age at the time Abraham attempted to sacrifice him, but it does give us enough information for us to arrive at an approximate answer.
The first detail that gives us some indication of Isaac’s age is found in Genesis 22:6.
Genesis 22:6 And Abraham took the wood for the burnt offering and laid it on his son Isaac, and he took in his hand the fire and the knife. So the two of them walked on together.
When Abraham, Isaac, and the two other men arrived at Moriah, Abraham gave Isaac the wood for the sacrifice to carry up the mountain. Isaac must have been old enough to have the strength to carry a large amount of wood. So he could not have been a young boy.
A second detail to note is the word “boy,” which Abraham uses in Genesis 22:5 to refer to Isaac. The same word is used to refer to Ishmael in Genesis 21:12, when he was a little more than thirteen years old (see Genesis 16:15–16; 17:1). So Isaac may have been a teenager.
Finally, Genesis 17:17 tells us that Sarah was ninety years old when God told Abraham she would conceive Isaac, and Genesis 23:1–2 says she died at the age of 127. So Isaac could not have been more than 37 years old during the events of Genesis 22.
Besides the text of Scripture, we can consider history and tradition. For example, first-century Jewish historian Josephus said, “Now Isaac was twenty-five years old” (The Antiquities of the Jews, 1.13.2). According to rabbinic tradition, Isaac was 37 years old (Ibn Ezra's Commentary on the Pentateuch, Genesis 22.5.1).
In Pastor Armstrong’s teaching on Genesis he stated that the events of Genesis 22 probably occurred twenty or more years later than the events of Genesis 21 and maybe as much as thirty years later. Given the information above, an age of twenty to thirty years would be a reasonable estimate.