Aang: Why did the Fire Nation start this war?

Iroh: Ah. Some people say it is within our nature to expand and consume like fire itself. Others believe that true stability in this world can only happen under our rule, so the drive to conquer is a drive for peace and unity.

Aang: But peace comes from respecting life, not killing and destroying.

Iroh: A noble sentiment, Avatar, but in the end, for most of us, it doesn't matter how this war started. It only matters how it can end.