Plato calls God « the Unlimited » in the Parmenidesi – but he calls him « the Limit » in the Philebusii. Contradiction? No, not really.
He calls God « Unlimited » because He receives no limit from anything, and he calls it « the Limit » because He limits all things according to their form and measure.
Marsilio Ficino notes that matter itself imitates God in this. It can be called « unlimited » because it represents « like a shadow, the infinity of the one God ». And it is « limited » as all things are, in some form.
The infinity of matter and the infinity of things can be described philosophically, using the three Platonic categories of « essence », « other » and « movement ». The world, shadow of God, generates infinitely in matter essences, alterations, transformations and movements.
The limit of matter, like the limit of all things, can also be philosophically described using the Platonic categories of « being », « same » and « rest ».
The Unlimited and the Limit are in the same relationship as the sun and the shadow. This is not an opposition ratio, but a ratio of generation. Through shade, one can probably better « see » (understand) the light of the sun than by looking at it directly.
If the « Unlimited » were a sun, then the innumerable essences, the infinite ‘othernesses’, the incessant movements would be its cast shadows.
And we would find the Limit in ideas, the idea of Being, the idea of the Same, the idea of Rest.
iParmenides 137d
iiPhilebus 16d-23c