As related by the Pāli Canon, the Enlightened One spent his first seven days at the root of the Bodhi Tree (Tree of Enlightenment), near Uruvelā by the banks of the River Nerañjarā, feeling the bliss of deliverance.
At the end of seven days, he emerged from that concentration, his mind occupied with dependent arising. In forward order, he thought:
That comes to be when there is this; that arises with the arising of this; that is to say: It is with ignorance as condition that formations come to be; with formations as condition, consciousness; with consciousness as condition, name-and-form; with name-and-form as condition, the sixfold base; with the sixfold base as condition, contact; with contact as condition, clinging; with clinging as condition, being; with being as condition, birth; with birth as condition, aging and death come to be, and also sorrow and lamentation, pain, grief and despair; that is how there is an origin to this whole aggregate mass of suffering.
That was during the first watch of the night. During the second watch, he was occupied with dependent arising in reverse order:
That does not come to be when there is not this; that ceases with the cessation of this; that is to say: With cessation of ignorance there is cessation of formations…
During the third watch, he was occupied with dependent arising in both forward and reverse order.
The mind of the Enlightened One was also occupied with the three defilements of lust, hate, and delusion as follows. He surveyed the world with his Buddha eye and saw beings burning with the many fires and consumed with the many fevers born of these three defilements. He uttered this exclamation:
This world is anguished, being exposed to contact,
Even what the world calls self is in fact ill…
Having emerged from deep concentration, occupied with dependent arising in forward, reverse, and forward and reverse order, occupied with the three defilements and its effects on the many beings, the Enlightened One saw that liberation does not come about through (love of) being, nor does it come about through (love of) non-being. He thought:
Through the essentials of existence, suffering is; with all clinging exhausted, suffering is no more.
This is how the Enlightened One spent his first seven days (as related by the Pāli Canon). First, in deep concentration, feeling the bliss of deliverance. Then, by contemplating dependent arising, the effects of the three defilements on the many beings, and finally by affirming the cessation of suffering through the exhaustion of clinging.
(Note: This entry is a paraphrase of Bhikkhu Nānamoli’s The Life of the Buddha, pages 30 – 32.)