Sutta advice on obstacles and insults, similar to Epictetus' (Stoic) advice?

"He was ignorant of my other faults, else he would not have mentioned these alone."

The first quote this statement reminded me of was The Four Great References, which include,

In such a case, bhikkhus, the declaration of such a bhikkhu is neither to be received with approval nor with scorn. Without approval and without scorn, but carefully studying the sentences word by word, one should trace them in the Discourses and verify them by the Discipline. If they are neither traceable in the Discourses nor verifiable by the Discipline, one must conclude thus:

'Certainly, this is not the Blessed One's utterance; this has been misunderstood by that bhikkhu — or by that community, or by those elders, or by that elder.'

In that way, bhikkhus, you should reject it. But if the sentences concerned are traceable in the Discourses and verifiable by the Discipline, then one must conclude thus:

'Certainly, this is the Blessed One's utterance; this has been well understood by that bhikkhu — or by that community, or by those elders, or by that elder.'

And in that way, bhikkhus, you may accept it on the first, second, third, or fourth reference. These, bhikkhus, are the four great references for you to preserve.

In summary, IMO a statement like, "He was ignorant of my other faults", is, "Certainly, not the Blessed One's utterance" (i.e. the Buddha wouldn't say that).

Now it is maybe an example of a "confession" (e.g. "I behaved wrongly, I was muddle-headed") -- which can be found in Buddhism, perhaps more especially in the Vinaya than the Suttas (though also in at least one Sutta I can think of).

Instead, the view that "I have faults" might be a kind of statement (or view) which Buddhism hopes you might abandon -- perhaps the anatta (non-self) view might suggest something like, "A fault has arisen ... but it is not "mine" ... I see the disadvantage of it, and resolve to not make a habit of it."

I don't know, are you familiar with the Christian tradition? The statement you quoted seems to be a reaction to being spoken ill of (along the lines of "turn the other cheek"). Whereas I think the Buddhist doctrine is more to be unmoved or unreactive, "neither welcoming praise nor rebelling against disgrace or blame" (Lokavipatti Sutta). Also (continuing the comparison with Christianity) the Buddhist seems to me to be closer to Christ's doctrine in the Gospels (e.g. "be ye perfect"), than it is to the Apostles' doctrines in the Epistles (e.g. "we are sinners").

A close sutta, very apposite to your question, might be Akkosa Sutta: Insult (SN 7.2) -- what the Buddha taught when someone tried to insult him.

On the other hand perhaps it's right to be honest about whatever faults you do (or did) have (see also "confession" above). I don't recall suttas which illustrate that side of the teacher (or "good friend") relationship, but AN 5.123 describes caring for someone who is physically ill, and says that a patient who is accurate and honest about their symptoms is easy to care for.

Also, getting onto the topic of "I have other faults" sounds to me like maybe papañca, and the "thicket of views" which we're warned is associated with self-view and with "attending inappropriately" (if I may say so without wanting to insult your Stoicism).

"What ought one to say then as each hardship comes? I was practising for this, I was training for this."

A good example of that might be the Punna Sutta.

Perhaps one difference though, notable, is that Punna's replies are not very self-centered ... not, "I was training for this", but rather, "they are very civilised" ... and, so, maintaining a mind of good will (see also the "Brahmaviharas" which summarise the appropriate social or inter-personal attitudes).

I think that maybe you can find statements from the Buddhist tradition, which are close to what you have in mind.

For example Is That So? is an example of, "do not make excuses about what is said of you"; or The Taste of Banzo's Sword an example of, "If you want to improve, be content to be thought foolish and stupid".

But I wanted to point out that the doctrine of the Pali suttas is comparable to, but, not the same as those Stoic statements.

The Sallekha Sutta (Effacement) prefaces many Stoic-like behavioral examples with this key observation:

Cunda, as to those several views that arise in the world concerning self-doctrines and world-doctrines, if [the object] in which[4] these views arise, in which they underlie and become active,[5] is seen with right wisdom[6] as it actually is,[7] thus: 'This is not mine,[8] this I am not,[9] this is not my self'[10] — then the abandoning of these views, their discarding,[11] takes place in him [who thus sees].

Consider that restraining the self, although wise, may not eliminate suffering entirely since the self can simply latch onto something else. If, however, one abandons the self, then wise behavior simply follows.

OP: "If anyone tells you that a certain person speaks ill of you, do not make excuses about what is said of you but answer, "He was ignorant of my other faults, else he would not have mentioned these alone."

Please see the Akkosa Sutta. It's similar. If you don't react to insults, it goes back to the originator.

Also from the Kalama Sutta:

"Now, Kalamas, one who is a disciple of the noble ones — thus devoid of greed, devoid of ill will, undeluded, alert, & resolute — keeps pervading the first direction [the east] — as well as the second direction, the third, & the fourth — with an awareness imbued with good will. Thus he keeps pervading above, below, & all around, everywhere & in every respect the all-encompassing cosmos with an awareness imbued with good will: abundant, expansive, immeasurable, free from hostility, free from ill will."

Be free from hostility and ill will, and be imbued with good will.

OP: "Bear and forbear"

Please see the Nakulapita Sutta:

"When this was said, the Blessed One said to me, 'So it is, householder. So it is. The body is afflicted, weak, & encumbered. For who, looking after this body, would claim even a moment of true health, except through sheer foolishness? So you should train yourself: "Even though I may be afflicted in body, my mind will be unafflicted." That is how you should train yourself.'

Let your mind be unafflicted.

OP: "What ought one to say then as each hardship comes? I was practising for this, I was training for this".

Please see the Maha-Saccaka Sutta:

"And how is one developed in body and developed in mind? There is the case where a pleasant feeling arises in a well-educated disciple of the noble ones. On being touched by the pleasant feeling, he doesn't become impassioned with pleasure, and is not reduced to being impassioned with pleasure. His pleasant feeling ceases. With the cessation of the pleasant feeling there arises a painful feeling. On being touched with the painful feeling, he doesn't sorrow, grieve, or lament, beat his breast or becomes distraught. When that pleasant feeling had arisen in him, it didn't invade his mind and remain because of his development of the body. When that painful feeling had arisen in him, it didn't invade his mind and remain because of his development of the mind. This is how one is developed in body and developed in mind."

When you face hardship, if you are developed in body and mind, you would not suffer from it.