My favourite has to be MN72. I think it is the best, most elegant description of conditionality and how it relates to the abayakata in the canon.
The basic idea is to compare the person with a fire and the undeclared with the cardinal directions (north, south, east and west):
“No wonder you don’t understand, Vaccha, no wonder you’re confused.
“Alañhi te, vaccha, aññāṇāya, alaṁ sammohāya.
For this principle is deep, hard to see, hard to understand, peaceful, sublime, beyond the scope of logic, subtle, comprehensible to the astute.
Gambhīro hāyaṁ, vaccha, dhammo duddaso duranubodho santo paṇīto atakkāvacaro nipuṇo paṇḍitavedanīyo.
It’s hard for you to understand, since you have a different view, creed, and belief, unless you dedicate yourself to practice with the guidance of tradition.
So tayā dujjāno aññadiṭṭhikena aññakhantikena aññarucikena aññatrayogena aññatrācariyakena.
so here we see the “beyond the scope of language/thought” argument.
Well then, Vaccha, I’ll ask you about this in return, and you can answer as you like.
Tena hi, vaccha, taññevettha paṭipucchissāmi; yathā te khameyya tathā naṁ byākareyyāsi.
What do you think, Vaccha?
Taṁ kiṁ maññasi, vaccha,
Suppose a fire was burning in front of you. Would you know:
sace te purato aggi jaleyya, jāneyyāsi tvaṁ:
‘This fire is burning in front of me’?”
‘ayaṁ me purato aggi jalatī’”ti?
so if you see you are a person…
“Yes, I would, Master Gotama.”
“Sace me, bho gotama, purato aggi jaleyya, jāneyyāhaṁ:
‘ayaṁ me purato aggi jalatī’”ti.
“But Vaccha, suppose they were to ask you:
“Sace pana taṁ, vaccha, evaṁ puccheyya:
‘This fire burning in front of you: what does it depend on to burn?’ How would you answer?”
‘yo te ayaṁ purato aggi jalati ayaṁ aggi kiṁ paṭicca jalatī’ti, evaṁ puṭṭho tvaṁ, vaccha, kinti byākareyyāsī”ti?
“Sace maṁ, bho gotama, evaṁ puccheyya:
“I would answer like this:
‘yo te ayaṁ purato aggi jalati ayaṁ aggi kiṁ paṭicca jalatī’ti, evaṁ puṭṭho ahaṁ, bho gotama, evaṁ byākareyyaṁ:
‘This fire burning in front of me burns in dependence on grass and logs as fuel.’”
‘yo me ayaṁ purato aggi jalati ayaṁ aggi tiṇakaṭṭhupādānaṁ paṭicca jalatī’”ti.
you would say this person depends on meat and air for fuel
“Suppose that fire burning in front of you was extinguished. Would you know:
“Sace te, vaccha, purato so aggi nibbāyeyya, jāneyyāsi tvaṁ:
‘This fire in front of me is extinguished’?”
‘ayaṁ me purato aggi nibbuto’”ti?
“Yes, I would, Master Gotama.”
“Sace me, bho gotama, purato so aggi nibbāyeyya, jāneyyāhaṁ:
‘ayaṁ me purato aggi nibbuto’”ti.
“But Vaccha, suppose they were to ask you:
“Sace pana taṁ, vaccha, evaṁ puccheyya:
suppose you see a person die of asphyxiation… (you can wait a while and let them disappear into dust)
‘This fire in front of you that is extinguished: in what direction did it go—
‘yo te ayaṁ purato aggi nibbuto so aggi ito katamaṁ disaṁ gato—
east, south, west, or north?’ How would you answer?”
puratthimaṁ vā dakkhiṇaṁ vā pacchimaṁ vā uttaraṁ vā’ti, evaṁ puṭṭho tvaṁ, vaccha, kinti byākareyyāsī”ti?
“It doesn’t apply, Master Gotama. The fire depended on grass and logs as fuel. When that runs out, and no more fuel is added, the fire is reckoned to have become extinguished due to lack of fuel.”
“Na upeti, bho gotama, yañhi so, bho gotama, aggi tiṇakaṭṭhupādānaṁ paṭicca ajali tassa ca pariyādānā aññassa ca anupahārā anāhāro nibbutotveva saṅkhyaṁ gacchatī”ti. Variant: ajali → jalati (sya-all, km, mr)
so to ask if a person is reborn, not reborn, both or neither, is like asking if when the fire went out it went out in the north the south the west or the east.
what one can say is that when the air ran out, no longer having fuel, the person ran out.
this is something true we can know and say about persons, that they die.
“In the same way, Vaccha, any form by which a Realized One might be described has been cut off at the root, made like a palm stump, obliterated, and unable to arise in the future.
“Evameva kho, vaccha, yena rūpena tathāgataṁ paññāpayamāno paññāpeyya taṁ rūpaṁ tathāgatassa pahīnaṁ ucchinnamūlaṁ tālāvatthukataṁ anabhāvaṅkataṁ āyatiṁ anuppādadhammaṁ.
A Realized One is freed from reckoning in terms of form*. They’re deep, immeasurable, and hard to fathom,
Rūpasaṅkhayavimutto kho, vaccha, tathāgato gambhīro appameyyo duppariyogāḷho—
like the ocean.
seyyathāpi mahāsamuddo.
this argument about persons is anterior to the anatta and aggregates material in the corpus.
It is an argument about the scope of language/logic/thought.
It starts as a response to the skeptics who claimed that one could not know if it was the “annihilationists” or the “eternalists” who where right.
this is all in DN1 and DN2 which are for various reasons* the most important texts for understanding early buddhism.
the buddha says that to a person who truly understands the above argument, everything salient to the questions of what one should do about the situations we find ourselves in become clear.
And that such a one truly knows that:
‘They’re reborn’, ‘they’re not reborn’, ‘they’re both reborn and not reborn’, ‘they’re neither reborn nor not reborn’—none of these apply.
Upapajjatīti na upeti, na upapajjatīti na upeti, upapajjati ca na ca upapajjatīti na upeti, neva upapajjati na na upapajjatīti na upeti.
So such a one truly knows that “you will not be reborn.” (i.e you will die an annihilationist death) doesn’t apply to them.
They truly know that “you will be reborn.” (i.e experience the eternal consequences in heaven(s) or hell(s)) doesn’t apply to them.
(this in itself would be something I would love to be able to claim for myself, but such a one knows even more than that!)
They truly know that “you will both be reborn and not reborn.” doesn’t apply to them.
and
They truly know that “you will neither be reborn, nor not reborn.” doesn’t apply to them.
The early buddhists understood something that the eternalists and nihilists and the skeptics all failed to understand, that there is “scope” to language/logic/thought, and that if we reflect on that fact the paradoxes of fate, time, space, existence and identity resolve completely.
The early buddhist argument did not rely on any particular meditative attainment to underwrite it, it stands on its own, and indeed is applied to the pre-existing jhana tradition of the nihilists in the exact same way it is applied to the determinists and the skeptics, and to the pre existing vedic practice of the brhama viharas.
MN72 is probably later than DN1 and DN2, but represents the best early metaphor for the deep understanding of the central philosophical argument of the early buddhist community.
It thankfully protects us from the delusion that the problem of human existence is the farcical notion that we simply don’t, which is what I think many of the people who make much of “anatta” think it all amounts to 
Anyway, some of this is probably for another thread.
*The longest suttas where clearly held in the highest esteem by the pre sectarian buddhists.
Firstly and most importantly, in the only intact canon in a middle indian language near contemporaneous with the buddhas, the long discourses are the first volume followed by the middle, then the connected, then the numerical, in that order.
Secondly the Vinaya of that corpus unequivocally states that it was the first 2 suttas of the long collection, by name.
Thirdly the Samyutta quotes from the long collection but the long does not quote from the connected, except and exactly where they can be demonstrated to not be pre-sectarian (usually by appeal to the chinese).
Fourth, it makes sense that the most prestigious collection would show the most evidence of pious “embroidery” and the long collection shows the most evidence of that.
Fifth, even if they are not the earliest they are certainly the most informative precisely because of their length, individually, compared to the lengths of narrative preserved in shorter narratives.
Sixth, doctrinally all the subsequent collections can be shown to depend on tropes that are preserved in their longest and least re-combined form.
