Why believe the bible?

[Minimalist]

Just politics...as usual.

https://en.wikipedia.org/wiki/Book_of_Genesis

As for why the book was created, a theory which has gained considerable interest, although still controversial is "Persian imperial authorisation". This proposes that the Persians of the Achaemenid Empire, after their conquest of Babylon in 539 BC, agreed to grant Jerusalem a large measure of local autonomy within the empire, but required the local authorities to produce a single law code accepted by the entire community. The two powerful groups making up the community—the priestly families who controlled the Temple and who traced their origin to Moses and the wilderness wanderings, and the major landowning families who made up the "elders" and who traced their own origins to Abraham, who had "given" them the land—were in conflict over many issues, and each had its own "history of origins", but the Persian promise of greatly increased local autonomy for all provided a powerful incentive to cooperate in producing a single text.[

Poor dripshit.  Suckered in by an ancient famly feud!