This is how I heard from the Blessed One. At one time, the Blessed One was staying in the city of Uruvelā on the bank of the river Nerañjarā at the foot of the Bodhi Tree, having just realised supreme enlightenment. There, the Blessed One was sitting cross legged for seven days straight experiencing the peace of liberation.
At the end of those seven days, the Blessed One emerged from that concentration and in the first watch of the night he reflected on the cause and effect method in reverse order as follows,
“Iti imasmiṁ asati idaṁ na hoti; imassa nirodhā idaṁ nirujjhati.
“When the cause doesn’t exist the relevant effect doesn’t exist. With the cessation of the cause the relevant effect ceases.
“Yadidaṃ avijjāyatveva asesa virāga nirodhā saṅkhāra nirodho. Saṅkhāra nirodhā viññāna nirodho. Viññāna nirodhā nāmarūpa nirodho. Nāmarūpa nirodhā saḷāyatana nirodho. Saḷāyatana nirodhā phassa nirodho. Phassa nirodhā vedanā nirodho. Vedanā nirodhā taṇhā nirodho. Taṇhā nirodhā upādāna nirodho. Upādāna nirodhā bhava nirodho. Bhava nirodhā jāti nirodho. Jāti nirodhā jarā maraṇaṁ soka parideva dukkha domanassupāyāsā nirujjhanti. Evametassa kevalassa dukkhakhandhassa nirodho hoti.”
“That is, with the cessation of ignorance, formation ceases. With the cessation of formation, craving ceases. With the cessation of consciousness, name and form ceases. With the cessation of name and form, six sense faculties cease. With the cessation of contact ceases, feeling ceases. With the cessation of craving ceases, clinging ceases. With the cessation of existence ceases, birth ceases. With the cessation of birth, aging, death, sorrow, weeping, pain, sadness, and sighing cease. This is the cessation of the whole mass of suffering.”
Then, the Blessed One who realised this cause and effect method as it really is spoke the following inspired verse,
The liberated one is energetic and meditates. At the time he is established in the aids to Enlightenment, all his doubts vanished. As a result, he realises the cessation of the conditions.