As one of the many biblical allusions, the name Ishmael refers to the son of Abraham and Hagar, the maid-servant of Abraham's wife Sarah. Since Abraham had no descendants because Sarah could bare no children, Sarah offered him her maid-servant. So Abraham took her as his second wife; however, it was the custom that any child conceived by this second wife would belong to the first wife and her husband. Learning this, Hagar fled when she was pregnant, but an angel of Yahweh told her to return and have the child because Abraham's descendants would be numerous. While this promise was extended to Ishmael, he was also cursed as Isaac was later born to Sarah and Abraham. After Isaac's birth, Sarah asked Abraham to expel Ishmael; he and his mother Hagar were released and roamed the desert afterwards.
Like his nomenclature, the narrator of Melville's novel, Moby Dick has no home and spends years on the sea. But, also like the biblical wanderer, Ishmael is also protected from death and survives the destruction of the Pequod, perhaps in order to retell the story of Ahab and the mysterious great white whale and to be evidence of the arbitrarinessof nature as well as proving that Moby-Dick is not completely an instrument of retribution.