"'But why make war at all, Dama?' Jardir dared to ask.
'Eh?' Khevat replied.
'We are all Everam's children,' Jardin said. 'The enemy is the alagai. We need every man to stand against him, yet we kill one another under the sun every day. Khevat looked at him, and Jardin was not sure if the dama was annoyed or pleased with the question.
'Unity,' the dama replied at last. 'In war men stand together, and it is that collective power that makes them strong. In the words of Kaji himself during his conquest of the green lands, "Unity is worth any price of blood. Against the night and Nie's untold legions, better a hundred thousand men standing together than a million cowering by themselves." Remember that always.'"
the sentiment explains a lot, both in the book and in the real world.