Steinbeck’s use of Old Testament material in East of Eden (1952) is very different from that in To A God Unknown (1933). As outlined in a previous article, Steinbeck was there qualifying the status of his protagonist, Joseph Wayne, by a number of literary means. But the most powerful qualifier of Joseph Wayne as prophet and saviour of his people is the manner in which Steinbeck contrives to keep the closely parallel story of the Joseph of Genesis ever-present throughout To A God Unknown. In East of Eden Steinbeck again, and indeed more obviously, makes use of Old Testament sources. But the Old Testament Cain and Abel do not loom reproachfully behind mere human characters in the book: when considered at all, they are considered explicitly and rationally in discussion, and in another sense the whole novel is clearly devoted to re-enactments of the episode and discussions of its significance.

Steinbeck sums up the centrality of the story in Journal of a Novel (1970), written during the composition of the first draft of East of Eden:

its framework roots from that powerful, profound and perplexing story in Genesis of Cain and Abel... this story with its implications has made a deeper mark in people than any other save possibly the story of the Tree of Life and original sin (90). It is using the biblical story as a measure of ourselves (105). However, Steinbeck’s adaptation of Genesis 4, 1-16 carefully excludes consideration of God, to whom, in Genesis, Cain and Abel offer their gifts. The blatant Cain-Abel correspondences in the novel are Charles and Adam Trask, and the twin boys Caleb and Aron Trask, ostensibly Adam’s sons, but, it transpires, probably like all of us sons of Cain, that is, of Charles.