Good comment.
One thing is certain, God will PROTECT Israel. There was a Psalm I believed it was talked about a few years back, Psalm 83 it I am not mistaken.
Those chapters from Genesis that you have mentioned, not only it is a warning against surgency or back in the day, have another woman have a baby for the woman that cannot have a baby on her behalf. The bad results we are seeing to this very day.
If you know the Bible, I wonder, does those chapters in Genesis proves that Ishmael was NOT legit born?
Not legit born?
The custom was to have many wives. Sarah told Abraham to take her hand maiden, Hagar, as a wife and he did.