Perhaps the most important contrast explored in this first section is that between the large, loving Hamilton family and the small, tension-ridden Trask family. In his portrayals of the patriarchs of these two families—Samuel Hamilton and Cyrus Trask, respectively—Steinbeck quickly establishes the different moral environments in which the children of the two families later develop. Samuel Hamilton is a powerful force of good and familial strength throughout the novel, whereas Cyrus Trask is a menacing figure of corruption and familial divisiveness. This initial contrast between the heads of the two families persists in the subsequent generations, as the Hamiltons remain close and loving while the Trasks are fraught with strife and hostility. We see this strife played out immediately in the next generation of the Trask family, as the good-natured and kind Adam frequently comes into conflict with the violent and manipulative Charles.

The biblical story of Cain and Abel, the sons of Adam and Eve, provides the basic template for many of the relationships in East of Eden—in the early parts of the novel, the relationship between. Charles and Adam. According to the Bible, Cain is a farmer, Abel a shepherd. When the two brothers bring sacrifices to God one day, Cain offers grain from his fields, while Abel offers the fattest portion of his flocks. God, seemingly arbitrarily, favors Abel’s offering over Cain’s. Cain then murders Abel out of jealousy. As punishment, God banishes Cain to the land of Nod, which lies “on the east of Eden”—hence the title of Steinbeck’s novel. In East of Eden, Charles and Adam mirror this biblical gift-giving in their birthday gifts to their father, Cyrus. Charles diligently saves money to buy Cyrus a German knife, while Adam, who hardly gives the gift a thought, presents Cyrus with a stray puppy he has found. Cyrus far prefers Adam’s gift to Charles’s, favors Adam in general, and even admits that he loves Adam more. Like Cain, Charles becomes intensely jealous and takes out his frustration on Adam, beating him brutally. But Charles, unlike Cain, does not kill his brother; for the moment, evil (Cain/Charles) and good (Abel/Adam) are locked in a struggle in which it seems that evil has the upper hand.