Harry had no strength to lift his head and see his savior’s identity. All he could do was raise a shaking hand to his throat and feel the place where the locket had cut tightly into his flesh. It was gone: Someone had cut him free. Then a panting voice spoke from over his head.

“Are — you — mental?”

Nothing but the shock of hearing that voice could have given Harry the strength to get up. Shivering violently, he staggered to his feet. There before him stood Ron, fully dressed but drenched to the skin, his head plastered to his face, the sword of Gryffindor in one hand and the Horcrux dangling from its broken chain in the other.

“Why the hell,” panted Ron, holding up the Horcrux, which swung backward and forward on its shortened chain in some parody of hypnosis, “didn’t you take this thing off before you dived?”

Harry could not answer. The silver doe was nothing, nothing compared with Ron’s reappearance; he could not believe it. Shuddering with cold, he caught up the pile of clothes still lying at the water’s edge and began to pull them on. As he dragged sweater after sweater over his head, Harry stared at Ron, half expecting him to have disappeared every time he lost sight of him, and yet he had to be real: He had just dived into the pool, he had saved Harry’s life.

Harry Potter and the Deathly Hallows – J.K. Rowling