Tite Kubo said this quote

In a world without fear of death... people will never attain the hope that is to be found from casting their fears aside and persevering through them. While it is true that people can continue to press forward through the simple act of living... That is in no way comparable to marching forward in the face of death while doing their damnedest to keep it at bay. That is why... that is why people have given that very march a unique and special name. Courage.