Sabbesaṃ vo, bhikkhave, subhāsitaṃ pariyāyena, api ca yaṃ mayā sandhāya bhāsitaṃ pārāyane metteyyapañhe:
Mendicants, you’ve all spoken well in a way. However, this is what I was referring to in ‘The Way to the Beyond’, in ‘The Questions of Metteyya’ when I said:
‘Yo ubhonte viditvāna,
majjhe mantā na lippati;
Taṃ brūmi mahāpurisoti,
The sage has known both ends,
and is not stuck in the middle.
He is a great man, I declare,
he has escaped the seamstress here (AN 6.61)
In Majjhesutta the Buddha give above verse from elsewhere.
Where to find pārāyana metteyyapañha? Is it Suttanipātapāḷi » Mettagūmāṇavapucchā (Snp 5.5)?
Are there any other suttas where the Buddha mention names of other suttas?
The two suttas in question here are the original statement Sn 5.2, and the subsequent discussion AN 6.61.
Using different symbolism MN 146 advises how to sever the attachments:
“This simile, sisters, I have given to convey a message. The message is this: The substance of the inner flesh stands for the six internal media; the substance of the outer hide, for the six external media. The skin muscles, connective tissues, & attachments in between stand for passion & delight. And the sharp knife stands for noble discernment — the noble discernment that cuts, severs, & detaches the defilements, fetters, & bonds in between.”
As well as stating wisdom is the ultimate emancipating factor, the idea conveyed here resolves a misunderstanding where arahants are believed not to feel anything. Life experience continues for the arahant, but they are detached from it. Thus they know both conventional and ultimate reality.
Magandiya sutta Sn 4.9
The Sutta Nipata is thought to be earlier, so its themes are often reiterated more expansively in later collections.
Bhante Sujato and Ajahn Brahmali have written about this in “The Authenticity of the Early Buddhist Texts”. See pp. 92-95.
There are also similar lists for doctrinal categories, specific teachings, similes, and verses.
" The Khuddaka Nikaya can easily be divided into two strata, one being early and the other late. The texts Sutta Nipata, Itivuttaka, Dhammapada, Therigatha (Theragatha), Udana and Jataka belong to the early stratum. The texts Khuddakapatha, Vimanavatthu, Petavatthu, Niddesa, Patisambhida, Apadana, Buddhavamsa and Cariyapitaka can be categorized in the later stratum"—‘A textual and Historical Analysis of the Khuddaka Nikaya’ – Oliver Abeynayake Ph. D. , Colombo, First Edition – 1984