It could be said that awareness and acceptance of one's own mortality is the fertile substrate of all spirituality. Contemplation of the finite and circumscribed nature of our existence can bring clarity and focus to our fundamental priorities in life, helping us to define and crystallize our unique, individual purpose for being on the planet.
Accepting our own death as natural and inevitable can free up reserves of wisdom and strength that would otherwise be tied up in deep-rooted existential dilemmas. Witness the tale of the Zen master who, when confronted by a conquering warlord enraged at his lack of deference and yelling "Don't you realize you are standing before a man who could run you through without blinking an eye!" calmly replied with "Do you realize that you are standing before a man who can be run through without blinking an eye?"
This tale also neatly demonstrates that the mortality equation has two sides: self and other. Just as we ourselves are mortal, so are others; and, what's more, we have the ability to end one another's mortal existence. This allows for the contemplation of any number of hypothetical (or not so) scenarios as a potentially rich source of self-insight. Here is one such:
You are in a cage suspended over a vat of boiling acid. In another cage suspended over the same vat is a violent, psychopathic criminal predator. There is a button in your cage. When the mad scientist who designed the whole experiment says "go", you have five seconds to push the button. If you push the button within five seconds, the other cage will drop into the acid, relegating the criminal psychopath to a swift but painful demise, and your cage will swing free, allowing you to escape. If you don't push the button, the opposite will happen, relegating you to a swift and painful demise while allowing the criminal psychopath to go free, almost certainly to prey on future victims. Would you push the button?
We all have both an inner Zen master and an inner warlord. The acceptance of death when it is inevitable can, in fact, coexist alongside an implacable resolution to do whatever is necessary to avert it when it is not, even when what is necessary is injuring or killing another human. The potent combination of acceptance and resolution makes for a powerful energetic aura that radiates self assurance and inner confidence under all circumstances.