The celestial Gods therefore, according to Plato subsisting after this manner, and the unity in each of them ineffably proceeding from the fountain of good, it is evident that they are all of them beneficent, and after a similar manner the causes of good. The bodies also which are suspended from their divine souls possess indescribable powers, some indeed being firmly established in the divine bodies themselves, but others proceeding from them into the nature of the world and into the world itself, descending in an orderly manner through the whole of generation, and without impediment extending as far as to particulars. With respect to the powers therefore, which remain in the divine celestial bodies themselves, there can be no doubt but that they are all similar; hence those powers remain to be considered which are sent to this terrestrial region, and are mingled with generation.
These then descend after the same manner for the safety of the universe, and connect with invariable sameness the whole of generation. They are likewise impassive and immutable, though they arrive at that which is mutable and passive. Generation indeed, being multiform, and consisting of things of a different nature, it receives the unity and simplicity of these Gods through its appropriate contrariety and division, in a hostile and partible manner. It likewise receives that which is impassive passively: and in short it participates of these Gods according to its own nature, and not according to their power. Hence, as that which is generated participates of being according to a flux of existence; and body participates of an incorporeal nature corporeally; thus also the natural and material substances which are in generation, participate of the immaterial and etherial bodies which are above nature and generation, in a confused and disorderly manner. Those therefore are absurd who attribute colour, figure and contact to intelligible forms, because the participants of them are coloured, figured and tangible; and they are no less absurd who ascribe evil to the celestial bodies, because the participants of them are sometimes evil. For there could be no participation, if the participant was not different from that which it participates. But if that which is participated is received in something different from itself, this something different, is in terrestrial places that which is evil and disorderly.
This participation therefore, becomes the cause of the abundant difference in secondary natures, and also the mixture of material with immaterial influences. To which may be added likewise, as another cause, that what is imparted in one way, is received after another in these inferior realms. Thus for instance, the influence of Saturn is connective, but that of Mars motive. In these material realms however, the passive receptacle of generation, receives the former according to congelation and frigidity; but the latter according to immoderate heat. Hence, corruption and the privation of symmetry are to be ascribed to the alterant, material and passive nature of the recipients.
Farther still, the imbecility of material and terrestrial places, not being able to receive the genuine power and most pure life of the etherial natures, ascribes its own defects to first causes. Just as if some one being weak in his body, and not able to bear the vivifying heat of the sun, should falsely dare to say, influenced by his own infirmities, that the sun is not advantageous to health and life. A thing of this kind likewise, may take place in the harmony and temperament of the universe, I mean, that the same things which are salutary to the whole, through the perfection of the recipients and things received, may be noxious to the parts though their partible privation of symmetry. In the motion of the universe therefore, all the circulations preserve the whole world after a similar manner, though frequently one certain part is injured by another; just as in a dance, where the order of the whole choir is still preserved, though a foot or a finger may happen to be hurt. Again, to be corrupted, and to be changed, are affections connascent with particulars. But it is not proper to accuse on this account wholes and first causes, either as containing these in themselves, or as if these proceeded from them into these inferior realms. And thus it appears, that neither the celestial Gods themselves, nor their gifts are productive of evil.
The Six Books of Proclus, the Platonic Successor, on the Theology of Plato (vol. 2 of 2) · The Wunder Library — complete classics, free to read, with narration.