The Buddha said to the great king, "Now I ask you, as it is now is your physical body indestructible and living forever? Or does it change and go bad?"
"World Honored One, this body of mine will keep changing until it eventually becomes extinct."
The Buddha said, "Great king, you have not yet become extinct. How do you know you will become extinct?"
"World Honored One, although my impermanent, changing, and decaying body has not yet become extinct, I observe it now, and every passing thought fades away. Each new one fails to remain, but gradually perishes like fire turning to ashes. This perishing without cease convinces me that this body will eventually become completely extinct."
The Buddha said, "So it is."
"Great king, at your present age you are already old and declining. How do your appearance and complexion compare to when you were a youth?"
"World Honored One, in the past when I was young my skin was moist and shining. When I reached the prime of life, my blood and breath were full. But now in my declining years, as I race into old age, my form is withered and wizened and my spirit dull. My hair is white and my face is in wrinkles and I haven’t much time remaining. How can I be compared to how I was when I was full of life?"
The Buddha said, "Great king, your appearance is not declining so suddenly as all that."
The king said, "World Honored One, the change has been a hidden transformation of which I honestly have not been aware. I have come to this gradually through the passing of winters and summers. How did it happen? In my twenties, I was still young, but my features had aged since the time I was ten. My thirties were a further decline from my twenties, and now at sixty-two I look back on my fifties as hale and hearty. World Honored One, I am contemplating these hidden transformations. Although the changes wrought by this process of dying are evident through the decades, I might consider them further in finer detail: these changes do not occur just in periods of twelve years; there are actually changes year by year. Not only are there yearly changes, there are also monthly transformations. Nor does it stop at monthly transformations; there are also differences day by day. Examining them closely, I find that kshana by kshana, thought after thought, they never stop. And so I know my body will keep changing until it is extinct."
The Buddha told the great king, "By watching the ceaseless changes of these transformations, you awaken and know of your extinction, but do you also know that at the time of extinction there is something in your body which does not become extinct?"
King Prasenajit put his palms together and exclaimed, "I really do not know."
The Buddha said, "I will now show you the nature which is not produced and not extinguished. Great king, how old were you when you first saw the waters of the Ganges?"
The king said, "When I was three years old my compassionate mother led me to visit the Goddess Jiva. We passed a river, and at the time I knew it was the waters of the Ganges."
The Buddha said, "Great king, you have said that when you were twenty you had deteriorated from when you were ten. Day by day, month by month, year by year until you have reached your sixties, in thought after thought there has been change. Yet when you saw the Ganges River at the age of three, how was it different from when you were thirteen?"
The king said, "It was no different from when I was three, and even now when I am sixty-two it is still no different."
The Buddha said, "Now you are mournful that your hair is white and your face is wrinkled. In the same way that your face is definitely more wrinkled than it was in your youth, has the seeing with which you look at the Ganges aged, so that it is old now but was young when you looked at the river as a child in the past?"
The king said, "No, World Honored One."
The Buddha said, "Great king, your face is in wrinkles, but the essential nature of your seeing has not yet wrinkled. What wrinkles is subject to change. What does not wrinkle does not change. What changes will become extinct, but what does not change is fundamentally free of production and extinction. How can it be subject to your birth and death? So you have no need to be concerned with what Maskari Goshaliputra and the others say: that when this body dies, you cease to exist."
The king believed the words that he had heard, and he understood that when we leave this body, we go on to another. He and all the others in the great assembly were elated at having gained this new understanding.