There was Isaac, his son by his half sister Sara. Ishmael, his son by his handmaiden, Hagar and another half dozens sons by his wife Keturah. They populated the region.
The OT is just the history of the Israelites, written by them, for them about their relationship with God.
What do you suggest Christians do next Sunday morning in place of going to Church? And should we call them Christians? I think this whole Christian thing has something to do with "the OT (which) is just the history of the Israelites, written by them, for them about their relationship with God". There must be some reason why they believe the Jew Jesus is the Messiah. Or like tony Harvard Man do you think it all comes from Hollywood?
You better come up with a quick answer, millions and millions of "Christians" are going to be mighty confused. Not to mention your Islamic friends.
According to YOU. Some say Jesus never even lived you know. And what is the NT? Revisionist history perhaps. All points of view can be debated.