A wonderful passage, taken from Ennead I.6. The translation is drawn from this page.
VI. For, as the ancient Oracle declares, temperance, fortitude and every virtue, aye, and wisdom herself, are purifications. Wherefore the sacred mysteries are right when they say enigmatically that he that is not purified shall, when he cometh to the House of Hades, lie in the mud. For, through their baseness, the filthy are friends of the mire, just as swine, whose bodies are unclean, delight to wallow in it.
For what is true temperance unless it be not to give oneself up to the pleasures of the body, and to flee from them as being neither pure nor belonging to that which is pure? And fortitude is not to fear death; and death is the separation of the soul from the body. He who desires to become alone will not fear this. Again, great-ness of soul is contempt of mortal concerns, and wisdom is the exercise of intellect turned away from that which is below and leading the soul upward to the heights.
When therefore the soul is purified, she becomes form and reason, altogether incorporeal, intellectual, and wholly of the divine order whence is the fountain of beauty and all that is akin thereto.
The soul borne upwards towards intellect puts on a marvellous beauty. Intellect, and that which comes from Intellect, is the beauty which truly belongs to her and is not foreign to her; because, when united to It, and then only, is she truly soul. Wherefore it is rightly said that the beauty and good of the soul consist in her assimilation to God; for it is thence that her beauty comes and the gift of a better lot than her present one. Moreover, beauty is that which has real being, but ugliness is the nature opposite to this. It is this that is the first evil; just as beauty is likewise the first of things beautiful and good. Or it may be that goodness and beauty are one and the same. Therefore, we must investigate the beautiful and good, and the ugly and evil, by the same process; and in the highest rank we must place the Beautiful Itself, which is also the Good Itself, of which Intellect is the immediate emanation and the first beautiful thing. But soul is beautiful through Intellect, and other things are beautiful because they, in turn, are formed by the soul, whether it be in actions or in pursuits and studies. And as to bodies, when these are spoken of as beautiful, it is still the soul that makes them so; for she, as something divine, and as it were a portion of the Beautiful Itself, makes beautiful, in so far as its nature will permit, all that she touches and overcomes.
VII. We must ascend, therefore, once more to the Good, which every soul desires. If anyone has beheld It, he will know what I say, and in what manner It is beautiful, for it is as good that It is desired, and all appetency is towards goodness. But the attainment of the Good is for those who mount upward to the heights, set their faces towards them, and strip off the garments with which we clothed ourselves as we descended hither. Just as those who penetrate into the innermost sanctuaries of the mysteries, after being first purified and divesting themselves of their garments, go forward naked, so must the soul continue, until anyone, passing in his ascent beyond all that is separative from God, by himself alone contemplates God alone, perfect, simple and pure, from Whom all things depend, to Whom all beings look, and in Whom they are, and live, and know. For He is the cause of Being, Life and Intelligence. If, then, anyone beheld Him, with what love would he be inspired, with what desire would he burn, in his eagerness to be united with Him! With what bliss would he be overcome! He that has not yet beheld Him may desire Him as Good, but, to him that has, it is given to love Him as Beauty, to be filled with wonder and delight, to be overwhelmed yet unharmed, to love with true love and keen desire, to laugh at other loves, and to despise the things he formerly thought beautiful. Of such a nature is the experience of those who have beheld visions of Gods or angels—no more do they seek aught of the beauty of other bodies. What, then, shall we think of one who beheld The Beautiful Itself and by Itself, pure and untouched by flesh or body, existing neither in earth nor in heaven, because of Its very purity? For all these are contingent things and mixed, nor are they primary but proceed from It. If, therefore, he beheld That which provides for all things, which, remaining in Itself, gives to all and receives nothing into Itself, and if, remaining in the contemplation of This and tasting of Its bliss, he should be assumed into Its likeness, of what other beauty would he then have need? For This, since It is Beauty Itself and the First Beauty, makes those who love It beautiful and beloved. And this is the greatest and ultimate task which lies before the soul, for the sake of which all her toils are undertaken— not to be left without portion in that most sublime vision, to obtain which is to be blessed by the vision of blessedness, but not to obtain it is wretchedness. For not he that has no share of beautiful colours or bodies, or of power or dominion or kingship, is unfortunate; but he that lacks this one thing alone, for the sake of which it were well to let go the possession and kingship and rule of the whole earth and of the sea, aye, and of the heaven itself, if a man, by leaving behind all these and looking beyond them, might be converted to This and behold It.
VIII. What, then, is the way? What are the means? How shall a man behold this ineffable Beauty which remains within, deep in Its holy sanctuaries, and proceeds not without where the profane may view It? He that is able, let him arise and follow into this inner sanctuary, nor look back towards those bodily splendours which he formerly admired. For when we behold the beauties of body we must not hurl ourselves at them, but know them for images, vestiges and shadows, and flee to That of which they are reflections. For if a man rushes towards them, seeking to grasp them for Beauty Itself, then it will be as though he should desire to grasp a beautiful image mirrored in water, and, like him of whom the myth tells, should sink beneath the surface of the stream and disappear. In like manner, he that reaches out after corporeal beauties, and will not let them go, will plunge not his body but his soul into gloomy depths abhorred by intellect, will remain blind in Hades, and both here and hereafter will have converse only with shadows.
How truly might someone exhort us—”Let us, then, fly to our dear country.” What therefore is this flight, and how shall we escape, like Odysseus in the story, from the enchantments of Circe and Calypso? There it tells symbolically how he remained unsatisfied although pleasant spectacles met his eyes and he was surrounded with all the beauty of sense. Our Fatherland is that country whence we came, and there our Father dwells. What, then, are the means for our escape thither? Our feet will not take us there, for all they can do is to carry us from one part of the earth to another. Nor will it avail to make ready horses for a chariot or ships on the sea: all these things we must let go. We must not even look, but with our eyes all but closed we must exchange our earthly vision for another, and awaken that, a vision which all possess but few use.
IX. What, then, does this interior vision see? When it is but lately awakened it cannot behold splendours too dazzling. The soul, therefore, must be accustomed first of all to contemplate beautiful pursuits, and next beautiful works, not those which are executed by craftsmen but those which are done by good men. After this, contemplate the souls of those who are the authors of such beautiful actions. How, then, may you behold the beauty of a virtuous soul? Withdraw into yourself and look; and if you do not yet behold yourself beautiful, do as does the maker of a statue which is to be beautiful; for he cuts away, shaves down, smooths and cleans it, until he has made manifest in the statue the beauty of the face which he portrays. So with yourself. Cut away that which is superfluous, straighten that which is crooked, purify that which is obscure: labour to make all bright, and never cease to fashion your statue until there shall shine out upon you the godlike splendour of virtue, until you behold temperance established in purity in her holy shrine. If you have become this, and have beheld it, and dwell within yourself in purity, and there is now nothing which prevents you from thus becoming one, when you have nothing foreign mingled with your interior nature, but your whole self is true light and light alone, not measured by size nor circumscribed by the limitation of any figure, not to be increased in magnitude because unbounded, but totally immeasurable, greater than all measure and mightier than every quantity—if you behold yourself grown to this, having now become vision itself, take courage and ascend yet higher, for now you need a guide no more. Gaze intently and see! This eye alone beholds that mighty Beauty. But if it approach the vision bleared by vices, unpurified, or weak through cowardice, so that it cannot bear to gaze upon such glory, then it sees nothing, even though another should be at hand to point out that which all may see. For he that beholds must be akin to that which he beholds, and must, before he comes to this vision, be transformed into its likeness. Never could the eye have looked upon the sun had it not become sun-like, and never can the soul see Beauty unless she has become beautiful. Let each man first become god-like and each man beautiful, if he would behold Beauty and God. For he will first arrive in his ascent at the region of Intellect and there he will know all the beauties of form, and will say that this is the beauty of Ideas, for all things are beautiful through these, the offspring and essence of Intellect. But that which is beyond Intellect we call the nature of the Good, from which the Beautiful radiates on every side, so that in common speech it is called the First Beauty. But if we distinguish between the Intelligibles, we may say that Intelligible Beauty belongs to the world of Ideas, but that the Good which is beyond these is the fountain and principle of the Beautiful. Or the Good and the First Beauty may be considered under one principle, apart from the beauty of the world of Ideas.