People all say that after 60 you age year by year; after 70, you age month by month; after 80, you age day by day. I am more than 80 years old--now what? From now on, each day I live is a day lent by Heaven for the Way--how dare I waste it? Even if I attain the Way right now, it is already late--how could it be admissible to delay any further?
A long time ago three elders were talking about impermanence. One elder said, "Of those who attend this year's party, who knows who will be missing next year." Another elder said, "What you're talking about is far away. When we take off our shoes and socks tonight, we don't know whether or not we will put them on again tomorrow." The third elder said, "What you're talking about is still remote. When we exhale this breath, we don't know if we will breathe in again."
The wise do not lose time, the brave do not think twice. If you get to know the Way today, you should set to work this very day; when you know, that is when to start. If you say you do not have the leisure today and will wait for another day, I'm afraid that when you want to do it you won't be able to anymore.
Human beings have three treasures--vitality, energy, and spirit. In old age, beware of exhausting vitality; when vitality is exhausted, you die. In old age, beware of leaking energy; if energy is drained, you die. In old age, beware of dissociation of the spirit; if the spirit is gone, you die.
How can you avoid exhausting vitality? Is it necessary to stay away from sex? How can you avoid dissociation of spirit? Is it necessary to be desireless? The spirit cannot be stabilized by force; when the mind and breathing rest on each other, then the spirit naturally stabilizes. Energyis not to be drained casually; forget words and keep centered and energy is not drained. Vitality is not to be lost through leakage; recirculate vitality to replenish the brain and vitality does not leak.
Some ask, when people age and their physical energy has deteriorated, how can it be replenished? By being careful of your speech you can replenish your lungs. By moderating food and drink you can replenish your stomach. By stopping worry you can replenish your heart. By getting rid of anger you can replenish your liver. By stopping promiscuous lust, you can replenish your kidneys and generative organs.
If asked for more, I would say don't worry about not replenishing; beware of replenishing and then wasting again. I have therefore said, after a hundred days of replenishment you do not see excess; but one day of waste and you sense insufficiency.
Look at the plants and trees; their foliage flourishes then drops in late autumn, returning to the roots as a natural pattern. Returning to the root, it does not die but regenerates come springtime. From this principle we can see that endless regeneration is the Way of nature, while returningto their roots is the inherent pattern of beings. Those who know the inherent pattern and do not violate the Way are real people. This is why "real people breathe from their heels"--the heels are like the root. During the three months of winter, which is the season of return to the root, you should quietly nurture this.