St Maximus, Amb. 22 (literal translation).

But the rational account (λόγος) of God, insofar as it is more perfect, is also more difficult to attain. For there are more objections (ἀντίληψεις) to it, and the solutions are more laborious.

If the things which have come to be are many, the things which have come to be are entirely different, if indeed they are many. For it is not possible that the many not also be different. And if the many are different, then one should also think to be different the reasons (λόγοι) in which they exist according to essence – the reasons in which, or rather because of which, the different things differ – since the different things would not differ from each other if the reasons (λόγοι), in which they came to be, did not differ. If then, just as, naturally and from necessity, the senses, apprehending (ἀντιλαμβάνομεναι) the sensations, during the reception [of these sensations], produce many and different apprehensions (ἀντιλήψεις) of the objects proposed and submitted to them, so also, naturally, the intellect, apprehending (ἀντιλαμβανόμενος) all the reasons (λόγοι) in beings, contemplating (ἐνθεωρῶν) in these the infinite operations (ἐνέργειαι) of God, produces many and, to speak the truth, infinite difference (διαφοραί), through which it apprehends (ἀντιλαμβάνεται) the divine operations (ἐνέργειαι); so in all likelihood, it will hold to be weak the power and unfollowable the method of scientific research into the really true being, as not having understanding how God – truly not being any of the beings, and chiefly being all things and above all things – is in each reason (λόγος) of each thing existing per se, and is in all the reasons (λόγοι) together, according to which all things exist.

If then it is properly in accord with the true rational account (λόγος) that every divine operation intimates, through itself, the whole God, without partition, in each according to a certain reason (λόγος), then who precisely is the one capable of understanding and saying how the whole God is in each thing commonly and in each of the beings particularly, without partition and undividedly, neither being variously separated into infinite differentiations (διαφοραί) within the beings in which he is, nor therefore being contracted according to the particular existence of the one, nor contracting the differences of the beings into one singular wholeness, but truly being all in all, never being displaced from his own simplicity without partition? Therefore, well did the teacher say that the “objections” (ἀντιλήψεις) of the rational account (λόγος) of the divinity are many, from which we learn only that God is; and [well did the teacher say] that “the solutions are more laborious,” from which again we learn what God is not, for the cessation of unprofitable and harmful curiosity on the part of those supposing the divine to be apprehended (ληπτόν) by the empty constructions of their reasoning, with which not even the last reason of the things in being, according to which they are and exist, truly is apprehended.