Symbolism, Imagery, Allegory
The Book of Enoch is a book in the Ethiopian Bible that details what happens to the fallen angels after they come to earth and have children with mortal human beings:
From reading […] Cabot began to understand […] He read about the fall of the angels, God speaking to Noah, the Great Flood. He read from his Bible and the Ethiopian one as well. He went back and forth from one to another, Genesis to Enoch. Enoch to Genesis. (12.10)
The Book of Enoch doesn't just serve as an introduction for Cabot Searcy to the world of religion—it leads him to the world of religious fanaticism. For him, Enoch becomes a door through which he can tap into his burgeoning ideas about his life, where it's going, and how unfair this God (who throws out fallen angels) can be. Instead of taking ownership for his own life and decisions, he uses the Book of Enoch as a reference guide and an excuse for the things that go wrong:
This had not been the first time Cabot had blamed God for the loss of his child. In fact, he had begun to write down lists of all the world's evils, as if he were building up an army of words to fight some heavenly battle. (16.8)
The Book of Enoch becomes the guiding light in his life, and helps him to justify his decisions when he does terrible things… like kidnap a random teenager. So on the level of Cabot, it represents failure to take responsibility.