This is how I heard. At one time, the Blessed One was living in the city of Sāvatthi, in Jeta’s park, at Anāthapiṇḍika’s monastery. The Blessed One addressed the monks, saying, “O monks!”
“Bhante!” those monks replied.
The Blessed One said, “Monks, this cycle of rebirth is endless. The beginning of this extremely long journey cannot be discovered. These beings, hindered by lack of knowledge of the true nature of life and bound by craving, roam and wander on in this endless journey. What do you think, monks, which is more: the mother’s milk that you have drunk as you roamed and wondered on in this long journey—this or the water in the four great oceans?”
“As we understand the Dhamma taught by the Blessed One, Bhante, the mother’s milk that we have drunk as we roamed and wandered on in this journey—this alone is more than the water in the four great oceans.”
“Good, good, monks! It is good that you understand the Dhamma taught by me in such a way. The mother’s milk that you have drunk as you roamed and wandered on in this journey—this alone is more than the water in the four great oceans.
“What is the reason for that? It is because, monks, this cycle of rebirth is endless. The beginning of this extremely long journey cannot be discovered. These beings, hindered by lack of knowledge of the true nature of life and bound by craving, roam and wander on in this endless journey.
“For such a long time, monks, you have experienced various types of suffering, tragedies, and disasters. You have filled the cemetery with your dead bodies. Therefore, monks, the time has come for you to understand the meaningless nature of all conditioned things. The time has come for you to become detached from them. And the time has come for you to be liberated from them.”