Plotinos: Complete Works

The first possibility is that there is a cause both for the things that become, and those that are; the cause of the former being their becoming, and that of the latter, their existence. Again, neither of them may have a cause. Or, in both cases, some may have a cause, and some not. Further, those that become might have a cause, while, of these that exist, some might partly have a cause. Contrariwise, all things that exist may have a cause, while of those that become, parts may have a cause, and part not. Last, none of the things that become might have any cause.
EXCEPT THE FIRST, ALL THINGS ARE CAUSED.
Speaking of eternal things, the first cannot be derived from other causes, just because they are first. Things dependent from the first, however, may indeed thence derive their being. To each thing we should also attribute the resultant action; for a thing's being is constituted by its displayed energy.