Bhagavad Gita, Chapter 11, Verse 32

The Deity said: I am the mighty world-destroying Time, here made manifest for the purpose of infolding the world. Even without you, none of the warriors arrayed in the hostile armies shall live.

Krishna says he is Time, the destroyer of worlds, and the outcome is already set.

Krishna doesn't offer a comforting metaphor, he names exactly what this form is. Whether or not Arjuna takes part, the outcome is described as already in motion.