What warning does king arthur receive in his dream?

In King Arthur's dream, he receives a warning about betrayal and impending doom. He envisions his knights being killed and the kingdom falling into chaos, which foreshadows the treachery that will come from within his own court. This dream serves as a cautionary message about the vulnerabilities of his reign and the dangers posed by those closest to him. Ultimately, it reflects the themes of loyalty and the fragility of power in Arthur's rule.