If you fight only for yourself, you fight with the strength of one man... If you fight with for your team, your school and your community, you fight with the strength of a few hundred man... If you fight for everyone you know and your country, then you fight with the strength of millions.
People live their lives bound by what they accept as correct and true. That's how they define "reality". But what does it mean to be "correct" or "true"? Merely vague concepts or their "reality" may all be a mirage. Can we consider them to simply be living in their own world, shaped by their beliefs?