In defending ERAS, many proponents point to 1 Cor. 15:28 as one of the primary texts that supports it (in addition to, say, 1 Cor. 11:3, John 6:38, and Matt. 26:39). In this passage Paul says,
When all things are subjected to him, then the Son himself will also be subjected to him who put all things in subjection under him, that God may be all in all.
The explanation of this passage from an ERAS framework is that, given the Son’s (supposedly divine) future subjection to the Father in this passage, it must also therefore be true that the Son has always submitted to the Father, even before the Lord’s acts of creation and redemption.
This is not how the early church, and particularly the pro-Nicene theologians who formulated the homoousion and its subsequent developments in the Nicene period, read this and other such passages. For instance, Basil says in Against Eunomius of 1 Cor. 15:28 that,
“If the Son is subjected to the Father in the Godhead, then He must have been subjected from the beginning, from whence He was God. But if He was not subjected, but shall be subjected, it is in the manhood, as for us, not in the Godhead, as for Himself.”
Note that Basil actually agrees with ERAS proponents in theory – if this passage speaks of the Son’s submission to the Father in his divinity, then it means that the Son has been subjected to the Father eternally. But Basil notes the temporal aspect of this passage (in other words, he’s being exegetically rigorous) and says that, given that the subjection takes place in time, it must therefore be referring to the Son’s actions in the temporal order, i.e. in his incarnate state.
Augustine speaks a number of times to this particular passage in De Trinitate, and expands on Basil’s understanding of the text as speaking to Christ’s submission in his humanity, not in his divinity.
“So there need be no hesitation from anyone in taking this to mean that what the Father is greater than is the form of a servant, whereas the Son is his equal in the form of God (I.15).
Note that Augustine here distinguishes between Christ’s humanity and divinity using the terms “form of a servant” and “form of God.” This tactic is employed in a number of other places, including other passages in which he discusses 1 Cor. 15:28. For instance, in Book I, section 20, he says:
So inasmuch as he is God he will jointly with the Father have us as subjects; inasmuch as he is priest he will jointly with us be subject to him.
And finally, in speaking about creatures seeing God face to face on the day of judgment, Augustine says in I.28,
This is to be a face to face seeing . . . when every creature is made subject to God, including even the creature in which the Son of God became the Son of man, for in this created form “the Son himself shall also be subject to the one who subjected all things to him, that God may be all in all (1 Cor. 15:28; emphasis mine).
The point is that, along with the other pro-Nicenes, Basil and Augustine eschew any hint of subordination within the Trinity, other than that of modes of subsistence (alternatively called taxis, or order). For the pro-Nicene theologians, there is no difference in authority, there is no submission, there is no functional subordination, except as it occurs in the humanity of the incarnate Son.