There is an entire chapter on detachment in the book. I am referring once again to the concept of attachment and detachment here. The exact phrase where that comes from is - 'Be in this world but not of this world.'
That means that we are here, we are participating in things but we don’t need to be involved in it. You can be in the middle of the war, but don’t let the war become you.
I recommend, you go back to the book and read the chapter on detachment.