[433] He was dwelling at Sāvatthī. … Then several bhikkhus approached the Blessed One … Sitting to one side, those bhikkhus said to the Blessed One: "Venerable sir, how many eons (kappa) have passed by and gone?"
"Bhikkhus, many eons have passed by and gone. It is not easy to count them thus: 'so many eons,' or 'so many hundreds of eons,' or 'so many thousands of eons,' or 'so many hundreds of thousands of eons.'"
"But, venerable sir, is it possible to give a simile?"
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.