Bhagavad Gita, Chapter 2, Verse 37

Dying, you gain heaven; conquering, you enjoy the earth. Therefore, O son of Kunti, arise, resolved to fight.

Win, and you rule. Fall, and you rise somewhere higher. Either way, this isn't a losing move.

Krishna lays out both outcomes plainly. Whichever way the battle goes, showing up for it leads somewhere worth going, so hesitation is the only real losing option.