Well, I know that! Abraham and Sarah were descendants of Adam and Eve. Aren’t we all descendants of Adam and Eve?
Yes, but being descendants of Adam and Eve doesn’t make us all Jews. You have to be descended from Abraham and Sara as well. But I’m referring to genetic Jews, not religious ones.
It has to do with being of the house and lineage of Abraham...then through the lineage of Isaac...then through the lineage of Jacob...from him came the 12 sons and founders of tribes of Israel...but it was to be thru Judah(one of the tribes) that Messiah would come.
Yes physically we all came from Adam....indeed Paul calls Christ the second Adam and all who Christians are descended and related thru the 2nd Adam. Yet God cut out and promised to be faithful to the house and lineage of Abraham...descended thru Isaac and Jacob. It was a spiritual covenant God made with Abraham.