"Christians" use Abraham's Age to Attack Scripture

 Recently in cyberspace a "progressive" Christian tried to undermine lifespans in Genesis among the first generations following the flood...in other words another liberal "Christian" denying Scripture...

Then Abraham fell on his face and laughed and said to himself, “Shall a child be born to a man who is a hundred years old? Shall Sarah, who is ninety years old, bear a child?” Genesis 17:17

"Genesis 17:17 — THE CLAIM: Abraham’s doubt about conceiving a child undermines the idea of patriarchs living for literally hundreds of years....THE ATTACK ON SCRIPTURE-

Genesis recounts the story of Abraham and Sarah who were old in age and had no children of their own. God appears to Abraham and says he will have a son in his old age, and

then in Genesis 17 it reads, “Then Abraham fell on his face and laughed and said to himself, ‘Shall a child be born to a man who is a hundred years old? Shall Sarah, who is 90 years old, bear a child?’” So Abraham thinks it’s biologically impossible for someone past the age of 100 to have a child. But this seems to contradict the ages of his ancestors, also known as the early patriarchs, who were supposed to live for hundreds of years and have children in their old ages. … More importantly is the fact that, based on what Genesis 12 says, Abraham’s own father Terah would have had to have fathered Abraham at his own age of 130.

RESPONSE by CMI--There are several problems with Jones’ reasoning. 

First, Abraham’s skepticism need not imply that this was a problem for earlier generations, just his own. 

This is true even if some in those earlier generations were still alive in Abraham’s day. It is true, for example, that Terah did not father Abraham until the age of 130 (compare Genesis 11:32; 12:4; Acts 7:4). 

But Abraham could have realized that lifespans were declining, so once he himself reached 100 he was already ‘old’, unlike his ancestors. Compare Jacob, Abraham’s grandson, who said to Pharaoh, “The days of the years of my sojourning are 130 years. Few and evil have been the days of the years of my life, and they have not attained to the days of the years of the life of my fathers in the days of their sojourning” (Genesis 47:9). 

This makes good sense if the patriarchal ages are literally accurate, and had gradually declined just as Genesis portrays. It also shows Jacob understood he was already near the end of his life at 130 (he died at 147), even though his grandfather Abraham lived to be 175 and his father Isaac 180. Isaac similarly thought he was approaching death at 133 because his eyesight had failed, although he actually had 47 years left to live.

 Second, the difficulty in conceiving a child likely had more to do with Sarah’s age than Abraham’s. Genesis 18:11 tells us that Sarah was post-menopausal, and it is significant that, in Genesis 17:17, Abraham mentioned not only his own age but Sarah’s as well. After all, Sarah had been barren in her youth, so a fortiori she would hardly be expected to be fertile after menopause." CMI