5 They have already inserted these expressions in their own writings. They sent them first to the man of God, Meletius, bishop, and after receiving from him a suitable reply, like mothers of monsters, ashamed of their natural deformities, these men themselves brought forth and bring up their disgusting offspring in appropriate darkness. They made an attempt too by letter on my dear friend Anthimus, bishop of Tyana, on the ground that Gregory had said in his exposition of the faith that Father and Son are in thought two, but in hypostasis one. The men who congratulate themselves on the subtlety of their intelligence could not perceive that this is said not in reference to dogmatic opinion, but in controversy with Ælian.
And in this dispute there are not a few copyists' blunders, as, please God, I shall show in the case of the actual expressions used. But in his endeavour to convince the heathen, he deemed it needless to be nice about the words he employed; he judged it wiser sometimes to make concessions to the character of the subject who was being persuaded, so as not to run counter to the opportunity given him. This explains how it is that you may find there many expressions which now give great support to the heretics, as for instance “creature” and “thing made” and the like.
But those who ignorantly criticise these writings refer to the question of the Godhead much that is said in reference to the conjunction with man; as is the case with this passage which they are hawking about. For it is indispensable to have clear understanding that, as he who fails to confess the community of the essence or substance falls into polytheism, so he who refuses to grant the distinction of the hypostases is carried away into Judaism. For we must keep our mind stayed, so to say, on certain underlying subject matter, and, by forming a clear impression of its distinguishing lines, so arrive at the end desired.
For suppose we do not bethink us of the Fatherhood, nor bear in mind Him of whom this distinctive quality is marked off, how can we take in the idea of God the Father? For merely to enumerate the differences of Persons is insufficient; we must confess each Person to have a natural existence in real hypostasis. Now Sabellius did not even deprecate the formation of the persons without hypostasis, saying as he did that the same God, being one in matter, was metamorphosed as the need of the moment required, and spoken of now as Father, now as Son, and now as Holy Ghost.
The inventors of this unnamed heresy are renewing the old long extinguished error; those, I mean, who are repudiating the hypostases, and denying the name of the Son of God. They must give over uttering iniquity against God, or they will have to wail with them that deny the Christ.
Source: Letters (New Advent)