A StickDaṇḍasutta

At Sāvatthī.Sāvatthiyaṁ viharati.

“Mendicants, this transmigration has no known beginning.“Anamataggoyaṁ, bhikkhave, saṁsāro. No first point is found of sentient beings roaming and transmigrating, shrouded by ignorance and fettered by craving.Pubbā koṭi na paññāyati avijjānīvaraṇānaṁ sattānaṁ taṇhāsaṁyojanānaṁ sandhāvataṁ saṁsarataṁ. Suppose a stick was tossed up in the air. Sometimes it’d fall on its bottom, sometimes the middle, and sometimes the end.Seyyathāpi, bhikkhave, daṇḍo uparivehāsaṁ khitto sakimpi mūlena nipatati, sakimpi majjhena nipatati, sakimpi antena nipatati; It’s the same for sentient beings roaming and transmigrating, shrouded by ignorance and fettered by craving. Sometimes they go from this world to the other world, and sometimes they come from the other world to this world.evameva kho, bhikkhave, avijjānīvaraṇā sattā taṇhāsaṁyojanā sandhāvantā saṁsarantā sakimpi asmā lokā paraṁ lokaṁ gacchanti, sakimpi parasmā lokā imaṁ lokaṁ āgacchanti.

Why is that?Taṁ kissa hetu? This transmigration has no known beginning. …Anamataggoyaṁ, bhikkhave, saṁsāro …pe… This is quite enough for you to become disillusioned, dispassionate, and freed regarding all conditions.”alaṁ vimuccitun”ti.