From The History of Philosophy, from the Beginning to Plato:

If this is so, then we need to steer a middle course: neither should we assume that Plato takes literally all the many ideas that he develops through his characters in the dialogues (which would be dangerous on any account), nor should we attempt to eliminate altogether what may seem to us the more fantastic and apparently poetic elements among them. (Indeed, for some Neoplatonist and Renaissance interpreters the latter probably take us closer to the core of Platonism.) We must remain aware that Plato’s philosophical writing is a complex matter, and that his motives as a writer may sometimes directly affect the content of that writing, as indeed may his chosen literary form. Thus, for instance, particular dialogues will often follow out a particular line of thought to the exclusion of others, which it is difficult to bring in within the fiction of a particular conversation (the treatment of immortality in the Symposium is one clear example; see above).

The ultimate goal of human life and of philosophy is to realize the mystical return of the soul to the Divine. Freeing itself from the sensuous world by purification, the human soul ascends by successive steps through the various degrees of the metaphysical order, until it unites itself in communion with the One.

Bindon, Peter. Neoplatonism: Rosicrucian Digest (Rosicrucian Order AMORC Kindle Editions) . Rosicrucian Order, AMORC. Kindle Edition.

From Physics:

This is why Plato in the Timaeus says that matter and space are the same; for the ‘participant’ and space are identical. (It is true, indeed, that the account he gives there of the ‘participant’ is different from what he says in his so-called ‘unwritten teaching’. Nevertheless, he did identify place and space.) I mention Plato because, while all hold place to be something, he alone tried to say what it is.

The belief that mind and body are two alien substances had a deadly effect on the psychology of man. It led to the belief that man is a “prisoner” of the body and therefore either must war against it, or seek escape from it if his mind is to be free. The true philosopher ought not to care about the pleasures of eating and drinking. In Plato’s Phaedo we read that “thought is best when the mind is gathered into herself and none of these things trouble her — neither sounds nor sights nor pain nor any pleasure, — when she takes leave of the body, and has as little as possible to do with it, when she has no bodily sense or desire, but is aspiring after true being.”[32]

Rushdoony, R. J.. The Flight From Humanity: A Study of the Effect of Neoplatonism on Christianity . Chalcedon/Ross House Books. Kindle Edition.

Theophilus of Antioch on the Popularity of Plato in an offhand remark while pointing out the vices of philosophers:

And regarding lawless conduct, those who have blindly wandered into the choir of philosophy have, almost to a man, spoken with one voice. Certainly Plato, to mention him first who seems to have been the most respectable philosopher among them, expressly, as it were, legislates in his first book,(4) entitled The Republic, that the wives of all be common, using the precedent of the son s of Jupiter and the lawgiver of the Cretans, in order that under this pretext there might be an abundant offspring from the best persons, and that those who were worn with toil might be comforted by such intercourse

Plato on immutability:

And what do you think of a second principle? Shall I ask you whether God is a magician, and of a nature to appear insidiously now in one shape, and now in another–sometimes himself changing and passing into many forms, sometimes deceiving us with the semblance of such transformations; or is he one and the same immutably fixed in his own proper image?

I cannot answer you, he said, without more thought.

Well, I said; but if we suppose a change in anything, that change must be effected either by the thing itself, or by some other thing?

Most certainly.

And things which are at their best are also least liable to be altered or discomposed; for example, when healthiest and strongest, the human frame is least liable to be affected by meats and drinks, and the plant which is in the fullest vigour also suffers least from winds or the heat of the sun or any similar causes.

Of course.

And will not the bravest and wisest soul be least confused or deranged by any external influence?

True.

And the same principle, as I should suppose, applies to all composite things–furniture, houses, garments: when good and well made, they are least altered by time and circumstances.

Very true.

Then everything which is good, whether made by art or nature, or both, is least liable to suffer change from without?

True.

But surely God and the things of God are in every way perfect?

Of course they are.

Then he can hardly be compelled by external influence to take many shapes?

He cannot.

But may he not change and transform himself?

Clearly, he said, that must be the case if he is changed at all.

And will he then change himself for the better and fairer, or for the worse and more unsightly?

If he change at all he can only change for the worse, for we cannot suppose him to be deficient either in virtue or beauty.

From the Enneads:

The One, as transcending Intellect, transcends knowing: above all need,
it is above the need of the knowing which pertains solely to the
Secondary Nature. Knowing is a unitary thing, but defined: the first is
One, but undefined: a defined One would not be the One-absolute: the
absolute is prior to the definite.

13. Thus The One is in truth beyond all statement: any affirmation is
of a thing; but the all-transcending, resting above even the most
august divine Mind, possesses alone of all true being, and is not a
thing among things; we can give it no name because that would imply
predication: we can but try to indicate, in our own feeble way,
something concerning it: when in our perplexity we object, “Then it is
without self-perception, without self-consciousness, ignorant of
itself”; we must remember that we have been considering it only in its
opposites.

If we make it knowable, an object of affirmation, we make it a
manifold; and if we allow intellection in it we make it at that point
indigent: supposing that in fact intellection accompanies it,
intellection by it must be superfluous.

Self-intellection — which is the truest — implies the entire
perception of a total self formed from a variety converging into an
integral; but the Transcendent knows neither separation of part nor any
such enquiry; if its intellectual act were directed upon something
outside, then, the Transcendent would be deficient and the intellection
faulty.

The wholly simplex and veritable self-sufficing can be lacking at no
point: self-intellection begins in that principle which, secondarily
self-sufficing, yet needs itself and therefore needs to know itself:
this principle, by its self-presence, achieves its sufficiency in
virtue of its entire content [it is the all]: it becomes thus competent
from the total of its being, in the act of living towards itself and
looking upon itself.

So when the universe was quickened with soul, God was well pleased; and he bethought him to make it yet more like its type. And whereas the type is eternal and nought that is created can be eternal, he devised for it a moving image of abiding eternity, which we call time. And he made days and months and years, which are portions of time; and past and future are forms of time, though we wrongly attribute them also to eternity. For of eternal Being we ought not to say ‘it was’, ‘it shall be’, but ‘it is’ alone: and in like manner we are wrong in saying ‘it is’ of sensible things which become and perish; for these are ever fleeting and changing, having their existence in time.

Plato, Timaeus (ca. 360 BC) 37C-38B, as quoted by R. D. Archer-Hind, The Timaeus of Plato (1888)