When the reader is introduced to Utterson in the first chapter, Utterson is presented as an extremely disciplined, almost puritanical man. Utterson is totally devoted to his work as a lawyer and refuses to grant himself even superficial pleasures. However, while Utterson is very disciplined when it comes to his own behavior, he doesn't really care what his friends do, as he outlines with this allusion:
“I incline to Cain’s heresy,” he used to say quaintly, “I let my brother go to the Devil in his own way.”
This line is a reference to the biblical book of Genesis. In the fourth chapter of Genesis, Cain famously murders his brother, Abel, and tries to hide his crime from God. When God asks where his brother is, Cain responds by asking, “Am I my brother’s keeper?” Cain’s denial of responsibility for his brother’s well-being is what Utterson is referencing (rather than the murder of Abel) when he speaks about “Cain’s heresy.”
With this reference, it seems like Utterson completely denies any responsibility for the actions or fate of his friends. To be sure, Utterson’s friends are adults and can bear the consequences of their own behavior. But Utterson goes beyond simply denying any responsibility to be their “keeper.” He says that he lets his friends “go to the Devil” in their own way. This implies an even greater degree of passivity on Utterson’s part, suggesting that he would allow his friends to misbehave to the point of self-destruction without intervention.
But this reading doesn’t quite square with Utterson’s well-documented and deep sense of loyalty. He is also introduced in this chapter as the “last good influence” in the lives of downwardly mobile young men. Utterson tries persistently to persuade Jekyll to open up about his problems (and eventually, to save him from them, in vain).
Utterson’s self-identification with Cain, even as (or perhaps because) it contradicts his behavior, opens up complex questions about his character. Is Utterson a loyal friend or an enabler of bad behavior? At what point is he obligated to intervene in the lives and decisions of his friends? These questions gain importance in light of Jekyll's decline throughout the book.
In Chapter 2, Utterson visits Dr. Lanyon, an old friend of his and Jekyll’s, to see if he has any information on Hyde. When Utterson broaches the topic of Lanyon’s friendship with Jekyll, the doctor recalls that they had fallen out around ten years prior due to professional disagreements. Jekyll’s scientific experiments became more and more “fanciful,” in Lanyon’s words. He uses an allusion to make this point:
“Such unscientific balderdash,” added the doctor, suddenly flushing purple, “would have estranged Damon and Pythias.”
Here, Lanyon alludes to the classical Greek legend of Damon and Pythias, a folk story set in the fourth century BC. Damon and Pythias were close friends who lived in Greek-occupied Sicily under the tyrant Dionysius I. In this legend, Dionysius condemns one of the two men (in most tellings, Pythias) to death. The condemned man begs to be allowed to return home one last time so that he can get his affairs in order.
His friend, Damon, offers himself up as a hostage, ready to die in his friend’s place should he never return. With this insurance, Dionysius allows the man to leave. When the appointed time for his execution comes, the condemned man returns just in time to free his friend. Impressed by their loyalty and courage, Dionysius frees them both.
Lanyon’s allusion to this story illustrates how deeply wrong Jekyll must have gone in his experiments; even the best of friends, he suggests, could not tolerate Jekyll's ideas. This is an early sign that there is more to Jekyll than his “nice guy” persona. But, as is so often the case in this novella, Lanyon will divulge no more about the matter, perhaps out of concern for Jekyll’s reputation.
The reference to this story of loyalty and sacrifice also gains particular meaning in the larger context of Lanyon’s friendship with Jekyll. Later on in the novella, when Jekyll needs a potion from his laboratory, Lanyon fulfills the request without question, doing so as faithfully as Damon offers himself for Pythias. In the legend, there is a latent possibility of self-destruction in Damon’s offer. Similarly, Lanyon’s willingness to help Jekyll ultimately proves fatal.