I thought it will be great to add what other said about Sthavira. For example Vasubandhu has a lot and sometimes even untraced suttas that is now lost. In the Chinese collection of 3 books by him of consciousness only. I found the following.
[The Sthaviras say that] although past and future do not exist, still, there are causes and effects that continue in a series.
Though the present stream of dharmas is extremely rapid, still
each dharma in the series has two phases of existence, a former state
and a subsequent one, a period of birth and a period of extinction.
When it is born, it repays its cause; when it perishes, it attracts a
result. Although there are these two phases or times, the substance of the dharma is unitary. Just as the prior cause perishes,
the subsequent result is born, and although substance and characteristics are distinct, both occur simultaneously. Thus cause and effect are not metaphors. However, there are no errors of cessation and permanence, nor any of the problems cited earlier. Who
of the wise would reject this and believe the other?
Of course there is response but we don’t those. Our intention must be to understand our Elders more because we have in later times become part of new sect. Also this I share as an example. We probably have enough to explain this. But a collection of others cited of sthaviras might give us more a background of the Elders in India.
It actually is part of THREE TEXTS ON
The first text by Demonstration of Consciousness Only
But He quoted a lot of Vasubandhu sources. The second and third book is said to be Vasubandhu.
Btw I also found this said
Scriptures of both the Sthaviras and the Vibhajyavadins, using a hidden meaning, call this consciousness bhavananga (bhava
Which removes the idea that According to the Sammatīya sect, the Vibhajyavādins developed from the Sarvāstivāda school.
Its kinda understandable then that if Sthaviras and Vibhajyavādins had some teaching the latter was a sub branch of sthaviras by read that they had their own scriptures it’s understandable each was different school.
And also there is untraceable suttas verses in Netti that can be shared.
Which is an accurate description of the Theravada doctrine, so that’s reassuring.
Another interesting one is the "lost: verse from the Ratana Sutta, which is found in the Mahavastu but not in Pali.
Like I like this from netti.
according as the Blessed One said Bhikkhus, I say that, relatively speaking,
all creatures, all breathing things, all beings, have one hindrance only, that is to say, ignorance; for all creatures have ignorance as hindrance. And bhikkhus, it is with the entire cessation of ignorance, with giving it up and relinquishing it, that creatures have no more hindrance, I say> ( …)
Actually until now the Vasubandhu book itself has not much to say about Sthavira. Maybe we might get some lost agamas suttas. For some traditions. Especially Sarvāstivāda.
Something nice also is the poem found in Mahaniddesa
Life, personhood, pleasure and pain
— This is all that’s bound together
In a single mental event
— A moment that quickly takes place.
Even the spirits who endure
For eighty-four thousand aeons
— Even these do not live the same
For any two moments of mind.
What ceases for one who is dead,
Or for one who’s still standing here,
Are all just the same aggregates
— Gone, never to connect again.
The states which are vanishing now,
And those which will vanish some day,
Have characteristics no different
Than those which have vanished before.
With no production there’s no birth;
With becoming present, one lives.
When grasped with the highest meaning,
The world is dead when the mind stops.
There’s no hoarding what has vanished,
No piling up for the future;
Those who have been born are standing
Like a seed upon a needle.
The vanishing of all these states
That have become is not welcome,
Though dissolving phenomena stand
Uncombined from primordial time.
From the unseen, [states] come and go,
Glimpsed only as they’re passing by;
Like lightning flashing in the sky
— They arise and then pass away.