In "The Sword of Summer" by Rick Riordan, the quote reflects on the themes of heroism and fate. It suggests that a hero who is not chosen correctly or has faced a wrongful death cannot find peace or fulfillment in the afterlife, specifically in Valhalla, the hall of the slain. This indicates that the path to heroism is fraught with challenges and critical choices that can determine one's destiny.

The second part emphasizes a looming event tied to the passage of time, with a mention of the sun traveling east. This suggests a significant transformation or awakening, where the Sword of Summer holds the key to unleashing a powerful creature. The urgency in this prophecy hints at an impending adventure filled with trials that the protagonist must navigate.