Near Rājagaha, in the Bamboo Grove. Then a certain brahmin went up to the Buddha, and exchanged greetings with him.
When the greetings and polite conversation were over, he sat down to one side and asked the Buddha, “Worthy Gotama, how many eons have passed?”
“Brahmin, many eons have passed. It’s not easy to calculate how many eons have passed, how many hundreds or thousands or hundreds of thousands of eons.”
“But worthy Gotama, can you give a simile?”
“I can,” said the Buddha.
“Consider the Ganges River from where it originates to where it meets the ocean. Between these places it’s not easy to calculate how many grains of sand there are, how many hundreds or thousands or hundreds of thousands of grains of sand. The eons that have passed are more than this. It’s not easy to calculate how many eons have passed, how many hundreds or thousands or hundreds of thousands of eons.
Why is that? This transmigration has no known beginning. No first point is found of sentient beings roaming and transmigrating, shrouded by ignorance and fettered by craving. For such a long time you have undergone suffering, agony, and disaster, swelling the cemeteries. This is quite enough for you to become disillusioned, dispassionate, and freed regarding all conditions.”
When he said this, the brahmin said to the Buddha, “Excellent, worthy Gotama! Excellent! … From this day forth, may the worthy Gotama remember me as a lay follower who has gone for refuge for life.”