Csdrhrt

I've heard a few pieces of advice the Buddha gave to arahants, but not much. What are some teachings the Buddha gave to arahants to guide them towards further growth?

(Edit)

I want to clarify a bit what I mean for I feel I didn't do an adequate job of explaining my question.

After enlightenment, there is nothing more to be done, but a phenomena seems to occur. The self is known to be illusory. The bodymind (the forms within experience that was previously identified with) continue to appear and slowly seems to embody the enlightened perspective.

This is outlined in this quote from this answer which was posted here on this forum in the past.

A Hinayana arhat abandoned afflictive obscurations by way of realizing emptiness, but has not abandoned knowledge obscuration. He has achieved abiding nirvana. Therefore, although they are free from the conception of true existence, and from true suffering, they are not free from the imprints of ignorance (i.e. knowledge obscurations). We say that it is like removing garlic from a container: the smell will still be there. So, because they still have the imprints of ignorance, (1) they are not free from the appearance of true existence, and (2) they are reborn with a mental body, due to the imprints of ignorance (in our case, we are reborn to due karma and afflictions).

A bodhisattva is a person who generated effortless bodhicitta (the wish to achieve enlightenment for the sake of all sentient beings). Since effortless bodhicitta is the entry gate to the Mahayana path, he entered the Mahayana small path of accumulation. When he cultivates wisdom, it is conjoined with emptiness and that makes his mind vast (due to bodhicitta) and profound (due to realizing emptiness). He wishes not to abide in individual liberation (abiding nirvana) but to be free from the extreme of peace (abiding nirvana) as well as from samsara. Therefore, he wishes to achieve non-abiding nirvana, which is the attainment of a buddha.

A Buddha abandoned both afflictive and knowledge obscuration, having generated the path perfection of wisdom (the wisdom of emptiness conjoined with bodhicitta). In his continuum, wisdom and bodhicitta are the same mind: the omniscient mind of a buddha that realizes all objects of knowledge directly, past present and future, in an unmistaken way, etc. He achieved non-abiding nirvana, abiding neither in samsara nor in individual liberation. His enlightened activities are uninterrupted.

This is apparently a quote from a zen master that illustrates the same thing.

A zen monk was once asked, “How’s your enlightenment going?” And he replied, “Fine. My body is having a hard time keeping up with it though.”

I am hoping to find content of this nature that describes how this process of going from an arahant to a Buddha unfolds.

There needs to be some caution/qualifications when discussing arahants just as there should be when discussing the Buddha. SN 44.1 discusses this caution and it applies to arahants as well.

"so too, great king, that form by which one describing the Tathagata might describe him has been abandoned by the Tathagata, cut off at the root, made like a palm stump, obliterated so that it is no more subject to future arising. The tathagata is liberated from reckoning in terms of form; he is deep, immeasurable, hard to fathom like the great ocean."

In SN 35.135:

I do not say of those bhikkhus who are arahants . . . that they still have work to do with diligence in regard to the six bases for contact. Why is that? They have done their work with diligence; they are incapable of being negligent.

There is one other teaching that I know of regarding what arahants do but I can't find it right now. In it the Buddha says that arahants continue to dwell with the 4 mindfulness established. Maybe someone else can find that reference?

What are some teachings the Buddha gave to arahants to guide them towards further growth?

Technically speaking, once one's attained arahantship, one'd continue training simply because the training has become second nature, a way of life, not because there's some further "growth" needed. A very common stock phrase that describes arahantship in many suttas:

"Birth is ended, the holy life fulfilled, the task done. There is nothing further for the sake of this world." ~~ Quote Refs ~~

Case 46 of the Mumonkan
Proceed On from the Top of the Pole 四十六　竿頭進歩

石霜和尚云、百尺竿頭、如何進歩。
Sekisõ Oshõ asked, "How can you proceed on further
from the top of a hundred-foot pole?"

又古徳云、百尺竿頭坐底人、雖然得入未爲眞。
Another eminent teacher of old said, "You, who
sit on the top of a hundred-foot pole, although you have entered the
Way you are not yet genuine.

百尺竿頭、須進歩十方世界現全身。
Proceed on from the top of the pole, and you will
show your whole body in the ten directions."

Mumon's Comment

無門曰、進得歩、翻得身、更嫌何處不稱尊。
If you go on further and turn your body about, no
place is left where you are not the master.

然雖如是、且道、百尺竿頭、如何進歩。嗄。
But even so, tell me, how will you go on further
from the top of a hundred-foot pole? Eh?"

Mumon's Verse
頌曰 瞎却頂門眼 He darkens the third eye of insight
錯認定盤星
And clings to the first mark on the scale.
拌身能捨命 Even though he
may sacrifice his life,
一盲引衆盲 He is only a blind man leading the
blind.

Or put very simply - seeing one's face for the first time does not perfect make us perfect Buddhas. It's really only the first mark on the scale. Some go so far as to say that our training doesn't really begin until we've had our dai kensho or great awakening experience. After enlightenment, there is still so much work left to be done! We still have to address what karmic obstacles remain and what insights into the nature of reality that we continue to miss. This means more meditation, more koans, more sesshins, and more sweat. In other words, post enlightenment training, that part of the path that turns us into perfect Buddhas, is basically identical to what came before. You proceed from the top of the pole in the same way that your climbed the first hundred feet. The tricky part is making that first step off the pole.