This famous first sermon of the Buddha was held near Bārāṇasi in the deer park of Isipatane. After his full enlightenment (see sutta 5.15.1,2,3) the Buddha dwelled under these respective trees for seven days each (bodhirukkhamūle; ajapālanigrodhamūle; mucalindamūle; rājāyatanamūle). The Mahāvaggo relates only these four weeks under the trees, the commentary and the Jātakanidāna make them 49 days–sattasattāha–seven times seven days–inserting three more weeks after the first–where the Buddha first sat with fixed gaze at the Bodhi tree (animisacetiya), then walked up and down (ratanacaṅkamacetiya), then meditated in the house of gems (ratanagharacetiya). Later he received his first food through the merchants Tapussa and Bhallika, who where the first to take refuge in the Buddha and the Dhamma: ‘ete mayaṃ, bhante, bhagavantaṃ saraṇaṃ gacchāma dhammañca, upāsake no bhagavā dhāretu ajjatagge pāṇupete saraṇaṃ gate’. At the end of his meditation under the Rājāyatana tree the thought not to teach Dhamma to others (one may also refer to introduction to lesson 1.3) arose in the Bhagavā:
….evaṃ cetaso parivitakko udapādi–‘adhigato kho myāyaṃ dhammo gambhīro duddaso duranubodho1 santo paṇīto atakkāvacaro2 nipuṇo paṇḍitavedanīyo. Ālayarāmā 3 kho panāyaṃ pajā ālayaratā ālayasammuditā. -….the following thought arose in his mind: “this Dhamma attained by me is profound, hard to perceive, difficult to comprehend, peaceful, excellent, not attainable by reason, subtle, intelligible to the wise. These beings indeed are attached to sensual pleasures, delighting in sensual pleasures and rejoicing in sensual pleasures.”
–Ālayarāmāya kho pana pajāya ālayaratāya ālayasammuditāya duddasaṃ idaṃ ṭhānaṃ yadidaṃ idappaccayatāpaccasamuppādo4 ; idampi kho ṭhānaṃ sududdasaṃ yadidaṃ sabbasaṅkhārasamatho5 sabbūpadhipaṭinissaggo6 taṇhākkhayo virāgo nirodho nibbānaṃ. Ahañceva kho pana dhammaṃ deseyyaṃ, pare ca me na ājāneyyuṃ, so mamassa kilamatho, sā mamassa vihesā”ti.–“For beings attached to sensual pleasures, delighting in sensual pleasures and rejoicing in sensual pleasures this is a matter difficult to perceive, that is the arising by cause and effect, it is further a matter far more difficult to perceive that is the calming of all mental conditioning, the complete eradication of all attachments, the extinction of craving, dispassion, cessation, Nibbāna. Therefore, if I were to teach the Dhamma and others were not to understand it would be weariness to me, it would be frustration to me.”
…–… ‘Kicchena me adhigataṃ, halaṃ dāni pakāsituṃ; rāgadosaparetehi, nāyaṃ dhammo susambudho. Paṭisotagāmiṃ7 nipuṇaṃ, gambhīraṃ duddasaṃ aṇuṃ8; rāgarattā na dakkhanti, tamokhandhena āvuṭā 9 .’…–… “What I have acquired through my hard work, why should I teach it, overcome by craving and aversion, they will not easily understand this Dhamma!’ Doing hard work that is subtle, profound, difficult to understand and minute, those who delight in craving and whose faculties are hindered by darkness will not see it!”
It was Brahma Sahampati, the ruler of the Brahma worlds, who understood the intention and then appeared in front of the Buddha and requested him to teach the Dhamma to the people in spite of his hesitation: ’Desetu, bhante, bhagavā dhammaṃ, desetu sugato dhammaṃ. Santi sattā apparajakkhajātikā 10, assavanatā dhammassa parihāyanti, bhavissanti dhammassa aññātāro’ – “May the Bhagavā teach, O’ Bhante, the Dhamma. May the Wellgone One teach the Dhamma. There are beings with little defilements, if they do not hear the Dhamma, they will come to ruin! They will understand the Dhamma!”
After the third time this request11 was repeated the Buddha approved and surveyed the world for beings, (see lesson 1.3.4) fit to be taught: ‘kassa nu kho ahaṃ paṭhamaṃ dhammaṃ deseyyaṃ? Ko imaṃ dhammaṃ khippameva ājānissatī’–To whom shall I teach Dhamma first, who will be able to grasp it quickly?
Out of gratefulness he remembered first his former teachers Āḷāra Kālāma and Udako Rāmaputto, but both had passed away. He then turned his thoughts to the five companions, who had left him before his final enlightenment (the pañcavaggiyā bhikkhū–the group of five; these are: Koṇḍañño, Vappa, Bhaddiya, Mahānāma, Assaji) and were dwelling at Isipatane. Isipatana migadāya was a sacred park with the history of many sages of former times (see footnote in the text). So the Buddha thought this to be a suitable location to set in motion the wheel of Dhamma and he visited them on the full moon day of Āsāḷha and preached this sutta.
The Dhammacakkappavattanasutta here is split in two parts (see lesson 3.2.3) according to the emphasis and suitability to the respective chapter.
 duranubodho: dur + anubodho: difficult + of comprehending, understanding
 atakkāvacaro: a + takka + avacaro: not + thinking + sphere, realm: beyond the range of thought, unthinkable
 ālayarāmā: ālaya + ārāma: hanging on, clinging + pleasure, delight
 idappaccayatāpaccasamuppādo: ida + paccayatā + paccasamuppādo: in this + on grounds, having a cause + arising because of a cause
 sabbasaṅkhārasamatho: sabba + saṅkhāra + samatho: all + mental conditioning + calming, appeasing
 sabbūpadhipaṭinissaggo: sabba + upadhi + paṭinissaggo: all + attachment, substratum to becoming + leaving behind
 paṭisotagāmiṃ: paṭi + sota + gāmiṃ: lit.: going against the stream
 aṇu: small, subtle
 āvuṭā: covered, hindered
 apparajakkhajātikā: appa +raja +akkha +jātikā: little + dust +with eyes +having
 The Mahā Buddhavaṃsā explains that in the case of every Buddha the highest being of the universe approaches the Enlightened One, pays respect and requests three times with these words that the Dhamma be taught. (See also lesson 1.3.3)