Из Дхаммапады:
225. Ahiṃsakā ye munayo, niccaṃ kāyena saṃvutā.
Te yanti accutaṃ ṭhānaṃ, yattha gantvā na socare.
225. Мудрецы, которые никого не обижают, чья плоть всегда смирена,
идут в неизменяемое место, и, придя туда, они не страдают.
Санкхата-лаккхана сутта:
"Monks, these three are fabricated characteristics of what is fabricated. Which three? Arising is discernible, passing away is discernible, alteration (literally, other-ness) while staying is discernible.
"These are three fabricated characteristics of what is fabricated.
"Now these three are unfabricated characteristics of what is unfabricated. Which three? No arising is discernible, no passing away is discernible, no alteration while staying is discernible.
"These are three unfabricated characteristics of what is unfabricated."
http://www.accesstoinsight.org/tipitaka/an/an03/an03.047.than.htmlВ 29 главе Патисамбхидамагги говорится, что Ниббана постоянна:
Pañcakkhandhe aniccato passanto anulomikaṃ khantiṃ paṭilabhati. Pañcannaṃ khandhānaṃ nirodho niccaṃ nibbānanti passanto sammattaniyāmaṃ okkamati.
Seeing the five aggregates as impermanent, he chooses in conformity; seeing how the cessation of the five aggregates is nibbana, which is permanent, he enters in the certainty of rightness.
...
Pañcakkhandhe anattato passanto anulomikaṃ khantiṃ paṭilabhati. Pañcannaṃ khandhānaṃ nirodho paramatthaṃ nibbānanti passanto sammattaniyāmaṃ okkamati.
Seeing the five aggregates as not self, he chooses in conformity; seeing how the cessation of the five aggregates is nibbana, which is the ultimate meaning (aim), he enters in the certainty of rightness.
Из 16 главы Висуддхимагги:
Tasmā appabhavameva, appabhavattā ajarāmaraṇaṃ, pabhavajarā maraṇānaṃ abāvato niccaṃ.
It is because of the absense of its creation and of its ageing and death that it [nibbana] is permanent.
...
Yathāvuttayuttisabbhāvato pana idameva niccaṃ, rūpasabhāvātikkamato arūpaṃ asitilaparakkamasiddhena ñāṇavisesena adhigamanīyato sabbaññuvacanato ca paramatthena nāvijjamānaṃ, vuttaṃ hetaṃ "Athī bhikkhave ajātaṃ abhūtaṃ akataṃ asaṅkhataṃ"[a]ti.
Because it can be arrived at by distinction of knowledge that succeeds through untiring perseverance, and because it is the word of the Omniscient One, nibbana is not-existent as regards individual essence in the ultimate sense; for it is said: 'Bhikkhus, there is an unborn, an unbecome, an unmade, an unformed' (Iti. 37; Ud. 80).