The ECCLESIASTICAL HistorY of Theodoret. Book I.
Chapter V.—The Letter of Eusebius, Bishop of Nicomedia, to Paulinus, Bishop of Tyre.
"To my lord Paulinus, Eusebius sendeth greeting in the Lord.
"The zeal of my lord Eusebius in the cause of the truth, and likewise your silence concerning it, have not failed to reach our ears. Accordingly, if, on the one hand, we rejoiced on account of the zeal of my lord Eusebius; on the other we are grieved at you, because even the silence of such a man appears like a defeat of our cause. Hence, as it behoves not a wise man to be of a different opinion from others, and to be silent concerning the truth, stir up, I exhort you, within yourself the spirit of wisdom to write, and at length begin what may be profitable to yourself and to others, specially if you consent to write in accordance with Scripture, and tread in the tracks of its words and will.
"We have never heard that there are two unbegotten beings, nor that one has been divided into two, nor have we learned or believed that it has ever undergone any change of a corporeal nature; but we affirm that the unbegotten is one and one also that which exists in truth by Him, yet was not made out of His substance, and does not at all participate in the nature or substance of the unbegotten, entirely distinct in nature and in power, and made after perfect likeness both of character and power to the maker. We believe that the mode of His beginning not only cannot be expressed by words but even in thought, and is incomprehensible not only to man, but also to all beings superior to man. These opinions we advance not as having derived them from our own imagination, but as having deduced them from Scripture, whence we learn that the Son was created, established, and begotten in the same substance and in the same immutable and inexpressible nature as the Maker; and so the Lord says, God created me in the beginning of His way; I was set up from everlasting; before the hills was I brought forth  .'
"If He had been from Him or of Him, as a portion of Him, or by an emanation of His substance, it could not be said that He was created or established; and of this you, my lord, are certainly not ignorant. For that which is of the unbegotten could not be said to have been created or founded, either by Him or by another, since it is unbegotten from the beginning. But if the fact of His being called the begotten gives any ground for the belief that, having come into being of the Father's substance, He also has from the Father likeness of nature, we reply that it is not of Him alone that the Scriptures have spoken as begotten, but that they also thus speak of those who are entirely dissimilar to Him by nature. For of men it is said, I have begotten and brought up sons, and they have rebelled against me  ;' and in another place, Thou hast forsaken God who begat thee  ;' and again it is said, Who begat the drops of dew  ?' This expression does not imply that the dew partakes of the nature of God, but simply that all things were formed according to His will. There is, indeed, nothing which is of His substance, yet every thing which exists has been called into being by His will. He is God; and all things were made in His likeness, and in the future likeness of His Word, being created of His free will. All things were made by His means by God. All things are of God.
"When you have received my letter, and have revised it according to the knowledge and grace given you by God, I beg you will write as soon as possible to my lord Alexander. I feel confident that if you would write to him, you would succeed in bringing him over to your opinion. Salute all the brethren in the Lord. May you, my lord, be preserved by the grace of God, and be led to pray for us."
It is thus that they wrote to each other, in order to furnish one another with weapons against the truth  . And so when the blasphemous doctrine had been disseminated in the churches of Egypt and of the East, disputes and contentions arose in every city, and in every village, concerning theological dogmas. The common people looked on, and became judges of what was said on either side, and some applauded one party, and some the other. These were, indeed, scenes fit for the tragic stage, over which tears might have been shed. For it was not, as in bygone days, when the church was attacked by strangers and by enemies, but now natives of the same country, who dwelt under one roof, and sat down at one table, fought against each other not with spears, but with their tongues. And what was still more sad, they who thus took up arms against one another were members of one another, and belonged to one body.