What message did Chaya tell her friends they must carry from the concentration camp if they survived?

From the text:

"Nevertheless," Hannah said, "I remember. And you—you must remember, too, so that whoever of us survives this place will carry the message into that future."

"What message?" Rivka asked, her voice breathy and low.

"That we will survive. The Jews. That what happens here must never happen again," Hannah said. "That. . ."