Abraham had two sons by his first marriage, one by his concubine Hagar, and one by his wife Sarah. Sibling rivalry became so intense that Isaac's mother demanded that Hagar and Ishmael be sent packing -- in the middle of the desert.
This injustice still rankles, thousands of years later. This sense of having been unjustly displaced. The Arabs of today trace their lineage back to wronged Ishmael. The Jews, to the favored golden boy, Isaac.
So who, then, are, the true sons of Abraham? The Christian answer is paradoxical -- none/all of the above:
Gal 3:26 Çünkü Mesih İsa'ya iman ettiğiniz için hepiniz Tanrı'nın oğullarısınız.Through faith in Jesus Christ, the gracious Creator's "graphic user interface" with the universe, His ultimate "avatar," any who enter into a covenant with the Creator can, once again, have a Father's undivided attention. We who believe in Jesus are the true descendants of Abraham, the inheritors of His promised goodness.
Gal 3:27 Vaftizde Mesih'le birleşenlerinizin hepsi Mesih'i giyindi.
Gal 3:28 Artık ne Yahudi ne Grek, ne köle ne özgür, ne erkek ne dişi ayrımı var. Hepiniz Mesih İsa'da birsiniz.
Gal 3:29 Eğer Mesih'e aitseniz, İbrahim'in soyundansınız, vaade göre de mirasçısınız.
 He had a number of children by his second wife, Keturah. By then, he'd already distributed the bulk of his estate, but he gave each of these additional sons a present and sent them packing when they came of age.