At Sāvatthi.

Then several bhikkhus approached the Blessed One. Having approached him, they paid homage and sat down to one side. Sitting to one side, those bhikkhus said this to the Blessed One: "Venerable sir, how many aeons have passed and gone by?"

"Many aeons, bhikkhus, have passed and gone by. It is not easy to count them as so many aeons, or so many hundreds of aeons, or so many thousands of aeons, or so many hundreds of thousands of aeons."

"Then, is it possible to give a simile, venerable sir?"

"It is possible, bhikkhus," the Blessed One said.

"Suppose, bhikkhus, there were four disciples here each with a life span of a hundred years, living a hundred years, and each day they were each to recollect a hundred thousand aeons. There would still be aeons not yet recollected by them when those four disciples each with a life span of a hundred years, living a hundred years, would pass away at the end of a hundred years. It is not easy to count them and say that they are so many aeons, or so many hundreds of aeons, or so many thousands of aeons, or so many hundreds of thousands of aeons.

For what reason? Bhikkhus, this cyclic existence is without a discoverable beginning. A first point is not discerned for beings who, obstructed by ignorance and fettered by craving, run on and wander in this cycle of existence. For such a long time, bhikkhus, you have experienced suffering, agony, and calamity, the cemetery has been filled up with your bones. Therefore, bhikkhus, it is enough to become disenchanted, to become detached and to become free from all conditions."