Like John Steinbeck's East of Eden, this novel seems to be a picture of legendary, folkloric nature. This comes from the intergenerational aspect of the book: it discusses the story of the first patriarch who (like Abraham) moves his family to a new land. Then his son, Zecheriah, rises up to take his father's place as the head of the farm. Zecheriah has a child with his wife, but also with his mistress (like Abraham and Jacob both).
In other words, this is a picture of the original sacrifices and hard work that brought this family forward in time from Tobias's extreme poverty to Solomon's extreme wealth. Also it's worth noting that Solomon is another Biblical name (commonly associated with unparalleled wealth).
Ultimately it would be wrong to read this text as a moralistic text. The debate between Solomon and his half brother Toby is ethical in nature, but the book itself doesn't take sides; it simply shows the facts of the matter, who said what and so forth. Instead of offering a picture of right and wrong ways of life, the book seems to show that sacrificing for the future of your family is the most important virtue, meaning that the debate at the end of the novel is merely an act of balance. This becomes clear in the denouement when the two brothers make peace, like Jacob and Esau.
