Q. I’ve looked at Psalm 90:10 and it seems to say an average Biblical life span is between 70-80 years. You’ve locked onto the 70 year figure. Aren’t you trying to make it fit your opinion? Couldn’t the magic number just as easily be 80? Or we could split the difference and call it 75. Why does it have to be 70 years?
A. Psalm 90:10 says,
“The length of our days is seventy years – or eighty if we have the strength … ” To me this means on average mankind will have a 70 year life span. Some of the stronger ones will exceed that, but most won’t, and current UN statistics show that many won’t even reach 70. But if you’re looking for something more concrete to confirm this, try Isaiah 23:15,
At that time Tyre will be forgotten for seventy years, the span of a king’s life.
Here it says that a king lives for 70 years. By the testimony of two witnesses a thing is confirmed (John 8:17). Moses (the author of Psalm 90) and Isaiah testify that a Biblical life span is 70 years.
I recently learned that among some branches of Judaism, a man who has reached the age of 83 will customarily celebrate a second bar mitzvah, under the logic that a “normal” lifespan is 70 years, so that an 83-year-old can be considered 13 in a second lifetime. (Jewish boys normally celebrate their first bar mitzvah at age 13.) This practice has become increasingly common. (Source: Wikipedia: bar and bat mitzvah)