So I have heard. At one time the Buddha was staying near Sāvatthī in Jeta’s Grove, Anāthapiṇḍika’s monastery. There the Buddha addressed the mendicants, “Mendicants!” “Venerable sir,” they replied. The Buddha said this: “Mendicants, this transmigration has no known beginning. No first point is found of sentient beings roaming and transmigrating, shrouded by ignorance and fettered by craving. Suppose a person was to strip all the grass, sticks, branches, and leaves in the Black Plum Tree Land, gather them together into one pile, and chop them each into four inch pieces. They’d lay them down, saying: ‘This is my mother, this is my grandmother.’ The grass, sticks, branches, and leaves of the Black Plum Tree Land would run out before that person’s mothers and grandmothers. 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.”

Linked Discourses 15.2 Chapter One The Earth