Nicene and Post-Nicene Fathers, Ser. II, Vol. III:
Life and Works of Rufinus with Jerome's Apology Against Rufinus.: Section 5

5. Now whereas we said that the Eastern Churches, in their delivery of the Creed, say, “In one God 3263 the Father Almighty,” and “in one Lord,” the “one” is not to be understood numerically but absolutely. For example, if one should say, “one man” or “one horse,” here “one” is used numerically. For there may be a second man and a third, or a second horse and a third. But where a second or a third cannot be added, if we say “one” we mean one not numerically but absolutely. For example, if we say, “one Sun,” here the meaning is that a second or a third cannot be added, for there is but one p. 545 Sun. Much more then is God, when He is said to be “one,” called “one,” not numerically but absolutely, that is, He is therefore said to be one because there is no other. In like manner, also, it is to be understood of the Lord, that He is one Lord, Jesus Christ, by or through Whom God the Father possesses dominion over all, whence also, in the next clause, God is called “Almighty.”

God is called Almighty because He possesses rule and dominion over all things. 3264 But the Father possesses all things by His Son, as the Apostle says, “By Him were created all things, visible and invisible, whether they be thrones, or dominions, or principalities, or powers.” 3265 And again, writing to the Hebrews, he says, “By Him also He made the worlds,” and “He appointed Him heir of all things.” 3266 By “appointed” we are to understand “generated.” Now if the Father made the worlds by Him, and all things were created by Him, and He is heir of all things, then by Him He possesses rule also over all things. Because, as light is born of light, and truth of truth, so Almighty is born of Almighty. As it is written of the Seraphim in the Revelation of John, “And they have no rest day and night, crying Holy, Holy, Holy, Lord God of Sabaoth, which was and which is and which is to come, the Almighty.” 3267 He then who “is to come” is called “Almighty.” And what other is there who “is to come” but Christ, the Son of God?

To the foregoing is added “Invisible and Impassible.” I should mention that these two words are not in the Creed of the Roman Church. They were added in our Church, as is well known, on account of the Sabellian heresy, called by us “the Patripassian,” that, namely, which says that the Father Himself was born of the Virgin and became visible, or affirms that He suffered in the flesh. To exclude such impiety, therefore, concerning the Father, our forefathers seem to have added these words, calling the Father “invisible and impassible.” For it is evident that the Son, not the Father, became incarnate and was born in the flesh, and that from that nativity in the flesh the Son became “visible and passible.” Yet so far as regards that immortal substance of the Godhead, which He possesses, and which is one and the same with that of the Father, we must believe that neither the Father, nor the Son, nor the Holy Ghost is “visible or passible.” But the Son, in that He condescended to assume flesh, was both seen and also suffered in the flesh. Which also the Prophet foretold when he said, “This is our God: no other shall be accounted of in comparison of Him. He hath found out all the way of knowledge, and hath given it unto Jacob His servant and to Israel His beloved. Afterward He shewed Himself upon the earth, and conversed with men.” 3268

Footnotes

Deum,not, as before, Deo.

Compare Cyril’s words, Quod omnium teneat potentatum—Lordship over all; ὁ παντοκράτωρ, ὁ πάντων κρατων, ὁ πάντων ἐξουσιάζων. (Catech., 8, §3). Rufinus evidently had St. Cyril’s exposition in view here as repeatedly elsewhere.

Col. i. 16

Heb. i. 2

Heb. iv. 8

Baruch iii. 35-37. Baruch is not specified by name in Rufinus’s list of the Canonical books, but it is in Cyril’s, as though a part of Jeremiah, “Jeremiah, with Baruch, and the Lamentations and the Epistle.” (Catech. 4, §36.)