2 Now they seek to exhibit the foundation for their dogma by citing the word in the law, “I am the God of your fathers: you shall have no other gods beside me;” and again in another passage, “I am the first,” He says, “and the last; and beside me there is none other.” Thus they say they prove that God is one. And then they answer in this manner: “If therefore I acknowledge Christ to be God, He is the Father Himself, if He is indeed God; and Christ suffered, being Himself God; and consequently the Father suffered, for He was the Father Himself.”
But the case stands not thus; for the Scriptures do not set forth the matter in this manner. But they make use also of other testimonies, and say, Thus it is written: “This is our God, and there shall none other be accounted of in comparison of Him. He has found out all the way of knowledge, and has given it unto Jacob His servant (son), and to Israel His beloved. Afterward did He show Himself upon earth, and conversed with men.” You see, then, he says, that this is God, who is the only One, and who afterwards did show Himself, and con-versed with men.
And in another place he says, “Egypt has laboured; and the merchandise of Ethiopia and the Sabeans, men of stature, shall come over unto you, (and they shall be slaves to you); and they shall come after you bound with manacles, and they shall fall down unto you, because God is in you; and they shall make supplication unto you: and there is no God beside you. For You are God, and we knew not; God of Israel, the Saviour.” Do you see, he says, how the Scriptures proclaim one God?
And as this is clearly exhibited, and these passages are testimonies to it, I am under necessity, he says, since one is acknowledged, to make this One the subject of suffering. For Christ was God, and suffered on account of us, being Himself the Father, that He might be able also to save us. And we cannot express ourselves otherwise, he says; for the apostle also acknowledges one God, when he says, “Whose are the fathers, (and) of whom as concerning the flesh Christ came, who is over all, God blessed for ever.”
Source: Against the Heresy of Noetus (New Advent)