Listen carefully: Unless a grain of wheat is buried in the ground, dead to the world, it is never any more than a grain of wheat. But if it is buried, it sprouts and reproduces itself many times over. In the same way, anyone who holds on to life just as it is destroys that life. But if you let it go, reckless in your love, you’ll have it forever, real and eternal.

My initial take on 'dead to the world' is about the perception of the world, or your own perception (although misinformed) of letting yourself willingly, blindly flow into seemingly counter-intuitive change.
I feel that the root of the act is about allowing yourself to enter a state of, seemingly hopeless surrender to what life has to offer and not clinging to any state of success or identity in which you currently live. This is the essence of living in faith. This is faith. Any clinging we do to people, traits, status, belongings, even life itself, is from fear of loss. This is not faith. You will soon be a stagnate pool of paralysis. Instead, let life and others flow and grow through you, sometimes empowering you and sometimes changing you completely.
When called to enter the ground one grain of wheat might ask, "This is crazy, I'm the ripest, plumpest, best shaped grain of wheat in this area, let alone from my stalk! Why would I willingly leave all of this prime social standing, that I've worked hard for, to dig myself into dirt and mud with no air, no wind and no sun? No, way. That sounds like a sure dead end to me. I'll stick to my success and personal achievement."
But that is a seed that will wither and break down in the dry wind and sun. Or maybe it will mold and rot with the rain. But, it will not reach its potential or carry forward a great life of giving and abundance.
Let go. Go into life wreckless in your love and Faith.