Sarah had a baby at 90 years old.
I have always imagined this great grandmotherly looking woman joyously caring for a baby. Doesn’t seem overly hard for God to juice her endocrine system for a special purpose.
But that is not how it worked.
In Genesis 20, in the three month window before Isaac’s conception, Abraham took her to Philistia. Before going, he asked her to do the “You are my sister thing” and sure enough, once there, she got picked up by the king himself to be part of his harem.
Now think about it.
You are a king. You have a harem. You would presumably be quite picky about who you add to your harem. Great grandmotherly looking women would not be at risk of your roving eye.
In other words, Sarah did not look 90 years old. God had not just juiced her endocrine system. He either kept her from aging, or rolled the clock back about a half a century or so for this occasion.
When Sarah was in Philistia, she had no wrinkles, no curvature of the spine, no grey hair, no creaky joints, no brown spots on her face or hands, no sagging anything, anywhere, no daily fiber pills to improve motility and no high blood pressure meds, ruining her liver.
She was home-coming-queen stunning at 90 years old.
Spry enough to chase a toddler around the yard and toss him in the air.
I think this is another expression of time and space. God manipulated the speed (time and space combined) of a million facets of her biology in order to keep all of her body systems sparkly.
I suspect part of aging is not only the slowing down of a system, but the desynchronization of various systems in the body.
She was in tune – everything in sync with everything else.
Because God can make any exception He wants to anyone’s time/space alignment.