"A stone had been dropped into the well, the well was my youthful soul. And for a very long time this matter of Cain, the fratricide, and the 'mark' formed the point of departure for all my attempts at comprehension, my doubts and my criticism."
In this quote, Sinclair ruminates about the effect of the initial conversation he had with Demian concerning the story of Cain. Demian suggested that the mark of Cain should be seen as something that distinguishes someone, rather than as a negative sign of Cain's malice. This interpretation is the first challenge ever presented to Sinclair's traditional Christian world- view. Just as a stone dropped in a well would have a rippling effect, disrupting all the water in the well, so too does this heretical interpretation have wide- ranging effects on Sinclair's soul. The imagery of the well, then, foreshadows Demian's further intellectual progress. This first departure from traditional Christianity serves a symbolic role for Demian later on; the story of Cain becomes a source of inspiration for him to dig deeper into what he is learning and to think more creative and original thoughts.
"You knew all along that your sanctioned world was only half the world and you tried to suppress the second half the way the priests and teachers do. You won't succeed. No one succeeds in this once he has begun to think."
Demian says this to Sinclair during the time they are taking Confirmation lessons together (Chapter 3). Here, he lets Sinclair know that he knows how Sinclair has been thinking. Demian forces Sinclair to face just what he has been feeling about the other realm. Demian roots out Sinclair's deepest desires, and shows Sinclair how he has been suppressing them. This is a particularly psychological moment, where Demian is essentially serving as Sinclair's psychoanalyst, uncovering what lies hidden in the depths of Sinclair's being. This also foreshadows Sinclair's future development. Demian, of course, turns out to be right—Sinclair eventually becomes unable to continue to suppress his desire to break out of the holy world.
"Suddenly, a new image had risen up before me, a lofty and cherished image. And no need, no urge was as deep or as fervent within me as the craving to worship and admire. I gave her the name Beatrice ."
This passage comes from Chapter 4, right after Sinclair has seen Beatrice in the park. It is here that Sinclair changes his behavior and resolves to become more serious. In Beatrice, he acquires a sort of god—something that gives meaning to his action and drives him to want to excel. Sinclair has seen the wonder of a radiant woman and felt close at hand the possibility of true love. This impels him to reform his behavior, be more creative, and strive to improve himself.
"We who bore the mark, felt no anxiety about the shape the future was to take. All of these faiths and teachings seemed to us already dead and useless. The only duty and destiny we acknowledged was that each one of us should become so completely himself, so utterly faithful to the active seed which nature planted within him, that in living out its growth he could be surprised by nothing unknown to come."
This quote comes from the middle of the seventh chapter, as Sinclair reflects on the time he spent in the Demian household. Here is an expression of the full force of the ideal toward which Demian has been leading Sinclair. Sinclair, at this point, recognizes and ascribes to this ideal; he has become one of those who bear the mark. This mark, of course, is the sign that singles out as special those like Demian, Frau Eva, and now, Sinclair, who subscribe to the ideal described here. This ideal champions the individual, prizing him above all else—particularly, antiquated religious and moral systems.
"Perhaps you'll need me again sometime, against Kromer or something. If you call me then I won't come crudely, on horseback or by train. You'll have to listen within yourself, then you will notice that I am within you."
Demian says this to Sinclair at the end of the book. Sinclair has been wounded in battle and calls for Demian. Demian comes to Sinclair and informs him that he will no longer come physically to help him. This marks Sinclair's true independence. Even toward the end of the novel, even when he was intellectually and emotionally ready to break free, he was still hanging out with Frau Eva and Demian. Sinclair was not yet independent. He had the two of them for comfort and support. Now, he will be physically alone. The fact that Demian is willing to set Sinclair on his path indicates a confidence he has that Sinclair is ready to face the world alone. Of course, Sinclair has been given an enormous set of tools with which to face potential problems. Though Demian may not be there in the flesh, Sinclair will be capable of doing anything Demian could—if he looks deep enough within himself.