Lily feels that Jonas and Gabriel must have some kind of connection because they have similar eyes.
Jonas’s father is a Nurturer. His job is to take care of Newchildren. When one of the Newchildren does not mature at the rate he is supposed to, Jonas' father gets special permission to bring him home. When Jonas’s father first brings baby Gabriel home, Lily points out the similarity between him and Jonas almost immediately.
"Isn't he cute? Look how tiny he is! And he has funny eyes like yours, Jonas!" Jonas glared at her. He didn't like it that she had mentioned his eyes” (Chapter 3).
Jonas has light-colored eyes, while almost everyone else in the community has darker eyes. He thinks Lily is rude for pointing out there is a difference, but Lily is a chatty little girl and does not realize the effect her pronouncement has on Jonas.
The lighter eyes seem to add depth to the baby’s expression, and Jonas realizes he probably seems the same way to people. He finds this unsettling.
Why would these two have the same color eyes, when no one else does? Lily has an idea about that, too:
Father put his bike into its port. Then he picked up the basket and carried it into the house. Lily followed behind, but she glanced back over her shoulder at Jonas and teased, "Maybe he had the same Birthmother as you" (Chapter 3).
Jonas ignores her, but in fact Lily is probably right. Children are not born to parents in Jonas’s community. Jonas and Lily are not related, but Gabe and Jonas probably are. Gabe will not be allowed to remain with Jonas’s family after his special extension, as only two children are allowed per family.
The light eyes are significant; they denote special powers. When Jonas first meets Gabe, he has no idea that he has the Capacity to See Beyond. As Jonas trains as Receiver of Memory, he learns that Gabe has it, too. Jonas is able to transmit memories to him. Jonas’s teacher, The Giver, also has light eyes.