The Bible

One thing Steinbeck does not do in his novel East of Eden is hide his references to The Bible, and if he does, he certainly does not do it very well.
As mentioned in a previous post, I believe there is a slight comparison between the brothers Adam and Charles Trask and the story of Abel and Cain, sons of Adam and Eve, and I want to continue biblical associations.
First of all, I believe the first instinct to associate Adam Trask with Adam from the Book of Genesis is well-founded and Steinbeck's intention, as I also believe Cathy, Adam Trask's wife, correlates with Eve.
I associate Cathy with Eve for the simple reason that Eve was the one was tempted by the serpent in the Garden of Eden and led to the downfall of man out of God's wrath. While Eve falls prey to evil itself, Cathy believes there is nothing but evil in the world and rather than attempt to change it or even sulk about this circumstance, she intends to live her life as richly as she can, causing as much pain to others for her own pleasure with no end goal in sight. The only true correlations between the biblical Eve and Cathy are their husbands and their association with sin.
Back to the original point, I associate Adam Trask with the biblical Adam for two reasons, because I don't think they share a first name out of mere coincidence, and because the main storyline connects Adam Trask's sons Aron and Cal with Abel and Cain, Adam's sons when I originally associated Adam Trask with Abel. I believe Adam's association with Abel is much stronger than his association with the biblical Adam, at least in childhood, but not much is really said about the biblical Adam in the first place.
The only comparison that works completely with the Bible is by correlating the story of Abel and Cain with Aron and Cal. Aron and Cal are the twin sons of Cathy and Adam, though she later claims that Charles is their father. Aron has always been the kind-hearted and likable boy, but is rather weak and easy to send over the edge. Cal was thought to be like Cathy and Charles early in life as he had evil tendencies from a young age and was always very jealous of his brother, but ended up wanting to improve himself and be more like his brother rather than do all he can to be above him.
As explained previously, Abel and Cain bring sacrifices to God. For Thanksgiving, Aron comes home from Stanford University and Cal plans to give $15,000 to his father as gift. Adam, always favoring Aron, is very excited at the prospect of his return. When presented with Cal's gift of money and learning its origin, he demands Cal return it to the farmers he had used to earn it through war profiteering, as he is already horrified that he has to send men to war by sitting on the draft board and does not want to profit off it. This reflects Cyrus's birthday gifts, as Adam viewed Aron's return as enough of a gift (Adam's pup) and was only angered by Cal's well thought out gift (to restore Adam's lost fortune).
In his rage, Cal takes Aron to Cathy's brothel, finally revealing the truth about their mother to Aron. After first coming in and meeting his mother, Aron looked "hurt, bewildered, despairing" and, in his horror, he "quietly went away" while Cal was "leaning against the door and laughing" (551, 548). Aron ends up joining the military after that night and dying in World War I. In this way, Cal's jealousy led him to hurt Aron by bringing him to meet their mother, which led him to join the military, and ultimately his death, thus completing the story of Abel and Cain.