Erin Hunter said this quote

She dabbed at the surface of the water with one paw, and the moon fluttered like silver wings before settling again as the water stilled. Letting out a faint mrrow of wonder, Half Moon dabbed again and again. However often she disturbed the surface, the moon was still there.“It doesn’t give up, does it?” Half Moon blinked at Jayfeather. “It’s always there, constant like the stones in this cave. Maybe we should be like the moon’s reflection, holding fast whatever happens?