"敵と戦うために生きる者は、敵が生き続けることに関心がある。"

Simplified Meaning:

When someone dedicates their life to fighting against an opponent, they actually need that opponent to stick around. For example, imagine a detective whose whole job is to catch thieves. If there were no thieves, the detective wouldn't have any work to do. This idea means that sometimes people or groups may not really want their opponent to disappear completely because their own work or purpose depends on having that enemy. To apply this to real life, think of any situation where a person is focused too much on an opponent or a problem. If they always have to fight against something, they might end up needing that problem just to feel useful or important. It's better to focus on positive goals and work towards building something good, rather than just fighting against something bad. This way, your sense of purpose doesn't depend on having an enemy.