The argument which you state is something like this:—Peter, James, and John, being in one human nature, are called three men: and there is no absurdity in describing those who are united in nature, if they are more than one, by the plural number of the name derived from their nature. If, then, in the above case, custom admits this, and no one forbids us to speak of those who are two as two, or those who are more than two as three, how is it that in the case of our statements of the mysteries of the Faith, though confessing the Three Persons, and acknowledging no difference of nature between them, we are in some sense at variance with our confession, when we say that the Godhead of the Father and of the Son and of the Holy Ghost is one, and yet forbid men to say “there are three Gods”? The question is, as I said, very difficult to deal with: yet, if we should be able to find anything that may give support to the uncertainty of our mind, so that it may no longer totter and waver in this monstrous dilemma, it would be well: on the other hand, even if our reasoning be found unequal to the problem, we must keep for ever, firm and unmoved, the tradition which we received by succession from the fathers, and seek from the Lord the reason which is the advocate of our faith: and if this be found by any of those endowed with grace, we must give thanks to Him who bestowed the grace; but if not, we shall none the less, on those points which have been determined, hold our faith unchangeably.

Ὁ μὲν οὖν λόγος, καθὰ προέφην, πολὺ τὸ δυσμεταχείριστον ἔχει: ἡμεῖς δέ, εἰ μέν τι τοιοῦτον εὕροιμεν, δι' οὗ τὸ ἀμφίβολον τῆς διανοίας ἡμῶν ἐρεισθήσεται, μηκέτι πρὸς τὸ διλήμματον τῆς ἀτοπίας ἐπιδιστάζον καὶ κραδαινόμενον, εὖ ἂν ἔχοι: εἰ δὲ καὶ ἀτονώτερος ἐλεγχθείη τοῦ προβλήματος ὁ ἡμέτερος λόγος, τὴν μὲν παράδοσιν ἣν παρὰ τῶν πατέρων διεδεξάμεθα φυλάξομεν εἰς ἀεὶ βεβαίαν τε καὶ ἀκίνητον, τὸν δὲ συνήγορον τῆς πίστεως λόγον παρὰ τοῦ κυρίου ζητήσομεν: ὃς εἰ μὲν εὑρεθείη παρά τινος τῶν ἐχόντων τὴν χάριν, εὐχαριστήσομεν τῷ δεδωκότι τὴν χάριν: εἰ δὲ μή, οὐδὲν ἧττον ἐπὶ τῶν ἐγνωσμένων τὴν πίστιν ἀμετάθετον ἕξομεν.