some time ago I was talking to a muslim about ishmael.
he was abrahams son, born to a slave woman.

found this just now :-


"Tell me, you who want to be under the law, are you not aware of what the law says?
For it is written that Abraham had two sons, one by the slave woman and the other by the free woman.
His son by the slave woman was born in the ordinary way; but his son by the free woman was born as the result of a promise.
These things may be taken figuratively, for the women represent two covenants.
One covenant is from Mount Sinai and bears children who are to be slaves: This is Hagar. Now Hagar stands for Mount Sinai in Arabia and corresponds to the present city of Jerusalem, because she is in slavery with her children.
But the Jerusalem that is above is free, and she is our mother. For it is written:
   "Be glad, O barren woman,
     who bears no children;
   break forth and cry aloud,
     you who have no labor pains;
   because more are the children of the desolate woman
     than of her who has a husband."[b]

Now you, brothers, like Isaac, are children of promise.
At that time the son born in the ordinary way persecuted the son born by the power of the Spirit. It is the same now.
But what does the Scripture say? "Get rid of the slave woman and her son, for the slave woman's son will never share in the inheritance with the free woman's son."[c]
Therefore, brothers, we are not children of the slave woman, but of the free woman."

Galatians 4: 21-31


[b] Galatians 4:27 Isaiah 54:1
[c] Galatians 4:30 Gen. 21:10

I'm not sure. I don't think so, not all arabs are muslims.
Have heard, ishmael is the father of arabs. Not necessarily muslims

But, think jews/xians follow Isaac, yes