Plato was asked at the very end of his life to sum up his whole life's work, his philosophy, he said simply, "Practice Dying".
I've always loved to hear it when masses of understanding and wisdom are summarized in a few words.
'The Course in Miracles' is done so in this way; - "Nothing real can be threatened, nothing unreal exists."
Osho was once asked to sum up Zen, he just said, "let go". He was asked what was the essence of Tantra, the ancient eastern mystical art/science, he said, "Accept and surrender to what is."
Time and again he has described all real religion as learning how to die. As I see it all of these statements are basically saying the same thing. The essence is to discover/understand/experience "what is", what is "real" i.e.
Life/Love/God/Nature/Dharma/Tao etc, ...then accept yourself as a part of it and surrender into it. To say, "Thy will be done".
Gradually all that's unreal dissolves or dies away (anything that can be lost was never truly yours) and you start to flow along with a deeper force and become your own destiny; to fulfill your potential, your purpose to experience your intrinsic nature. It's like a seed dying to become a tree. A caterpillar has to die in a sense to become a butterfly.
As Rumi said, "When have I ever become less by dying???"
Basically you are learning to trust, to have faith. You are moving from a closed fist to an open hand. This process can heal many people, who were on the verge of death.
Maybe Plato was saying why wait until then, let go now and be transformed? This is something we can practice from moment to moment. Dying to the past, dying to the known, dying to the false. Surrendering into the unknown. Trusting what "is". Trusting God.
That's why they say, "Let go and Let God". I think that there is another way in which we can practice dying, a different side to the coin.
Stephen Levine once asked, "If you had a year to live what would you do, who would you call, what would you say and why are you waiting?????????"
This could be a year, a month, a week, a day, an hour. Nothing is certain except the fact that each and every one of us will die. Knowing this (without fearing it) can inspire us, take us deeper into the present moment. Help us to live more fully and passionately. Encourage us to give everything of ourselves. To love, laugh, share and become closer to one another. To really live.
"Throughout the whole of life, one must continue to learn how to live, and what will amaze you even more, throughout life one must learn how to die." Seneca
"When Rabbi Birnham lay dying, his wife burst into tears. He said, 'What are you crying for? My whole life was only that I might learn how to die." Osho
"While I thought I was learning how to live, I was really learning how to die."
Leonardo Da Vinci