DN 17 B. Sujato in Ajahn Brahm's time machine goes back 84,000 years ago to Teach King Mahasudassana how to do "Jhāna"

First, note that DN 17 is describing a non Buddhist doing 4 jhanas and 4 brahma viharas.

King Mahāsudassana was a virtuous King, alive at a time where there were no Buddhas and Dharma instructions on how to realize nirvana and end rebirth.

The sutta DN 17 describes how this great King, even without a Buddha to instruct him, learned how to do 4 jhanas on his own, practiced the brahmaviharas, and was reborn in the Brahma realm at his time of death, dying peacefully in his sleep like someone falling asleep after a delicious meal. 

So you would think the sutta must be using the standard dictionary of words like vitakka and vicara (thinking and evaluation), kaya (physical body) that explain how to do the 4 jhanas. But looking at Sujato's translation below, it's evident the King was not using the standard dictionary of his time. It requires a secret decoder ring that only the prophet Sujato possesses, to explain that vitakka and vicara doesn't mean "thinking" (the same word thinking in the line before the jhanas describing 3 types of wrong thoughts), but vitakka actually means "placing the mind", "keeping it connected" to a secret unnamed kasina and bringing yourself into a formless frozen stupor where thoughts can't happen and the body disappears in 3rd jhana even though the word "kaya" the Buddha uses to describe it in third jhana is used consistently to refer to a physical body in similar meditation contexts (see MN 119). 

So the prophet Sujato has to go back to 84,000 years ago with  Ajahn Brahm and Buddhaghosa in their  time machine to let King Mahāsudassana know the secret codes and hidden explanations to absorb into an unnamed kasina and enter a frozen disembodied stupor.

In other words, there's no way King Mahāsudassana could do a "real jhana" (according to Sujato)  if he were to follow the plain straightforward language the Buddha used in the suttas. He needs the secret decoder ring to let him know about the kasina, and that when the sutta says, "think", it means "don't think, keep the mind frozen", and when it says "body", it means "not a physical body, but a mental body."

 How kind of Sujato to do this in-valuable service. What would we do without him?

SuttaCentral—sutta DN 17 Sujato Translation.

5. Attaining Absorption5. Jhāna-sampatti

Then King Mahāsudassana thought,Atha kho, ānanda, rañño mahāsudassanassa etadahosi:‘Of what deed of mine is this the fruit and result, that I am now so mighty and powerful?’‘kissa nu kho me idaṁ kammassa phalaṁ kissa kammassa vipāko, yenāhaṁ etarahi evaṁmahiddhiko evaṁmahānubhāvo’ti?

Then King Mahāsudassana thought,Atha kho, ānanda, rañño mahāsudassanassa etadahosi:‘It is the fruit and result of three kinds of deeds:‘tiṇṇaṁ kho me idaṁ kammānaṁ phalaṁ tiṇṇaṁ kammānaṁ vipāko, yenāhaṁ etarahi evaṁmahiddhiko evaṁmahānubhāvo, seyyathidaṁ—giving, self-control, and restraint.’dānassa damassa saṁyamassā’ti.

Then he went to the great foyer, stood at the door, and expressed this heartfelt sentiment:Atha kho, ānanda, rājā mahāsudassano yena mahāviyūhaṁ kūṭāgāraṁ tenupasaṅkami; upasaṅkamitvā mahāviyūhassa kūṭāgārassa dvāre ṭhito udānaṁ udānesi:‘Stop here, sensual, malicious, and cruel thoughts—‘tiṭṭha, kāmavitakka, tiṭṭha, byāpādavitakka, tiṭṭha, vihiṁsāvitakka.no further!’Ettāvatā, kāmavitakka, ettāvatā, byāpādavitakka, ettāvatā, vihiṁsāvitakkā’ti.

Then he entered the great foyer and sat on the golden couch. Quite secluded from sensual pleasures, secluded from unskillful qualities, he entered and remained in the first absorption, which has the rapture and bliss born of seclusion, while placing the mind and keeping it connected.Atha kho, ānanda, rājā mahāsudassano mahāviyūhaṁ kūṭāgāraṁ pavisitvā sovaṇṇamaye pallaṅke nisinno vivicceva kāmehi vivicca akusalehi dhammehi savitakkaṁ savicāraṁ vivekajaṁ pītisukhaṁ paṭhamaṁ jhānaṁ upasampajja vihāsi.As the placing of the mind and keeping it connected were stilled, he entered and remained in the second absorption, which has the rapture and bliss born of immersion, with internal clarity and confidence, and unified mind, without placing the mind and keeping it connected.Vitakka-vicārānaṁ vūpasamā ajjhattaṁ sampasādanaṁ cetaso ekodibhāvaṁ avitakkaṁ avicāraṁ samādhijaṁ pītisukhaṁ dutiyaṁ jhānaṁ upasampajja vihāsi.And with the fading away of rapture, he entered and remained in the third absorption, where he meditated with equanimity, mindful and aware, personally experiencing the bliss of which the noble ones declare, ‘Equanimous and mindful, one meditates in bliss.’Pītiyā ca virāgā upekkhako ca vihāsi, sato ca sampajāno sukhañca kāyena paṭisaṁvedesi, yaṁ taṁ ariyā ācikkhanti: ‘upekkhako satimā sukhavihārī’ti tatiyaṁ jhānaṁ upasampajja vihāsi.With the giving up of pleasure and pain, and the ending of former happiness and sadness, he entered and remained in the fourth absorption, without pleasure or pain, with pure equanimity and mindfulness.Sukhassa ca pahānā dukkhassa ca pahānā pubbeva somanassadomanassānaṁ atthaṅgamā adukkhamasukhaṁ upekkhāsatipārisuddhiṁ catutthaṁ jhānaṁ upasampajja vihāsi.

Then King Mahāsudassana left the great foyer and entered the golden chamber, where he sat on the golden couch.Atha kho, ānanda, rājā mahāsudassano mahāviyūhā kūṭāgārā nikkhamitvā sovaṇṇamayaṁ kūṭāgāraṁ pavisitvā rūpiyamaye pallaṅke nisinnoHe meditated spreading a heart full of love to one direction, and to the second, and to the third, and to the fourth. In the same way he spread a heart full of love above, below, across, everywhere, all around, to everyone in the world—abundant, expansive, limitless, free of enmity and ill will.mettāsahagatena cetasā ekaṁ disaṁ pharitvā vihāsi. Tathā dutiyaṁ tathā tatiyaṁ tathā catutthaṁ. Iti uddhamadho tiriyaṁ sabbadhi sabbattatāya sabbāvantaṁ lokaṁ mettāsahagatena cetasā vipulena mahaggatena appamāṇena averena abyāpajjena pharitvā vihāsi.He meditated spreading a heart full of compassion …Karuṇāsahagatena cetasā …pe…He meditated spreading a heart full of rejoicing …muditāsahagatena cetasā …pe…