"What if we can’t ever come back?" Isabelle said. The ruby around her neck was pulsing, glowing like a stoplight, illuminating her face.

Then at least we’ll be together,” Clary said, and looked around at her companions. She reached out and took Jace’s hand, and Simon’s hand on the other side of her, and held them tight. “We go through together, and on the other side we stay together,” she said. “All right?”

None of them answered, but Isabelle took Simon’s other hand, and Alec took Jace’s. They all stood for a moment, staring. Clary felt Jace’s hand tighten on hers, a nearly imperceptible pressure.

They stepped forward, and the shadows swallowed them up.

– City of Heavenly Fire: Chapter 13, Cassandra Clare