Abraham, Sarah and Hagar
The complicated story of the conception of Ishmael’s brother, Isaac, involves what are often considered by many opponents of “non-traditional families” the very things their biblical-inspired morality rails against. Thus, this bizarre love triangle becomes symbol of how families have always been constructed in “non-traditional ways.”
Ishmael and Sam
These characters are two titular dark sons of the novel. Because of the treatment they receive from their respective fathers—as well as their perceptions of that treatment—they become symbolic incarnations of betrayal at its most elemental level: between parents and children.
Isaac and David
Or does the title refer to the other sons in the novel, Isaac and David? These are the two “second sons” whom the Ishmael and Sam view as usurpers of their places. The perceived betrayal of their fathers is inextricably linked to the births of the two second sons. But in reality, these are not usurpers, but likable children. They come to symbolize how innocence can be victimized not through action, but the perception of others.
The Moving Van
The moving which Sam watches as it takes his father’s belongings away to his new home with a new family is one element of the two stories which cannot really be effectively duplicated in the biblical tale. It is very much a thing of its modern setting. And as such, it is used symbolically to illuminate how much easier it is to tear a family apart than it once was. The moving van is a powerful symbol of the fragility of modern day domesticity where all it takes to start over is transportation.
Prayer
Both Ishmael and Sam are shown in prayer in their respective stories. Prayer is usually addressed to God and God is often referred to as Father in those prayers. So, in effect, both sons are bypassing their actual fathers to speak directly with the Father of all. In this way, prayer comes to symbolize the means of communication with the lines of communication are obstructed or even severed.