Udana 1.1

Thus have I heard. On a certain occasion the Exalted One, soon after the attainment of Buddhahood, dwelt at Uruvela, on the banks of the stream Neranjara, at the foot of the tree of Enlightenment. At that time the Exalted One, after remaining in a sitting posture for seven days, experienced the joy of Emancipation.

When the seven days had come to a close, the Exalted One arose from the state of trance and in the first watch of the night, thoroughly thought out the chain of cause and effect, in direct order, thus: "If there is this state, another state arises, by the arising of this state, a state is produced, that is to say:

"From Ignorance spring Conformations, from Conformations springs Consciousness, from Consciousness spring Mind and Material Form, from Mind and Material Form, the six Organs of Sense, from the six Organs of Sense, Contact, from Contact, Sensations, from Sensations, Desire, from Desire, Attachment, from Attachment, Being, from Being, Birth, from Birth spring Decay, Death, Sorrow, Lamentation, Pain, Grief and Despair. Thus the whole mass of suffering originates." 

And the Exalted One in this connection, on that occasion, breathed forth this solemn utterance: 

"When the conditions of existence dawn upon the strenuous meditative Brahmana, 
When he understands the nature of cause and effect, 
Then all doubts depart." 

—all of the passages in this series are taken from the translation of the Udana by Dawsonne Melanchthon Strong (1902)