How we cite our quotes:
"Mother? Father?" he said, the idea coming to him unexpectedly, "why don't we put Gabriel's crib in my room tonight? I know how to feed and comfort him, and it would let you and Father get some sleep." (14.69)
Jonas reaches out to Gabriel as a result of his isolation. It says something about the futility of language that he connects best with an infant with whom he cannot communicate verbally.
Still patting rhythmically, Jonas began to remember the wonderful sail that the Giver had given him not long before: a bright, breezy day on a clear turquoise lake, and above him the white sail of the boat billowing as he moved along in the brisk wind.
He was aware of giving the memory; but suddenly he realized that it was becoming dimmer, that it was sliding through his hand into the being of the newchild. Gabriel became quiet. Startled, Jonas pulled back what was left of the memory with a burst of will. He removed his hand from the little back and stood quietly beside the crib. (14.76-77)
Remember when The Giver says that memories are meant to be shared? Exactly. Notice that Jonas forms such a close bond with Gabriel by transferring memories to him, an action he's not allowed to do with anyone else.
Jonas looked at her. She was so lovely. For a fleeting instant he thought he would like nothing better than to ride peacefully along the river path, laughing and talking with his gentle female friend. But he knew such times had been taken from him now. He shook his head. After a moment his two friends turned and went to their bikes. He watched as they rode away. (17.40)
In a way, Jonas's new awareness is what isolates him from his peers. He can't do normal things anymore, like go for walks or play war games, because he's aware of suffering in the world. Since no one else shares this knowledge, he bears his burden alone. Since bearing the burden is a constant and perpetual state of being, he can't ever be with others – at least not in any meaningful way.