Wayne Grudem, Bruce Ware, Owen Strachan et al. are all proponents of what is called Eternal Functional Subordination (EFS) or Eternal Submission of the Son (ESS) in regard to the Son’s relation to the Father. They claim to get this idea from biblical exegesis. But what is clear is that they actually get it from reading a prior socio-anthropological commitment into the Bible, as they see it, in support of their hard complementarianism as that relates to male-female relationships (particularly in the marriage bond). At a theological level, because they want to further bolster their socio-anthropological perspective, what they end up doing is conflating the economic reality of God’s triune life (ad extra) with God’s so called immanent life (ad intra); thus conflating processions and origin of relation with God’s missions as that is revealed in salvation-history. The result of this conflation (of collapsing the immanent into the economic tout court) is that the Son is eternally subordinate to the Father, in the ESS view, and the result is that we end up with some form of subordinationist theology proper; whether that be akin to something like Arianism or Monarchianism or Tri-theism (pick your poison).
In contradistinction from the ESS proponents, and in line with orthodox and historic teaching (meaning with reference to the ecumenical church councils and the Trinitarian as well as the Christological grammar produced) John Webster offers some prudential counsel on why we should reject the ESS position and call it what it is: heresy (he doesn’t use this word, but I infer it from his lengthy treatment of this topic of which the following is only one point of many). Here is Webster speaking directly to the eternal generation of the Son, and how that precisely does not support any sort of eternal subordination of the Son to the Father but in point of fact actually grounds the missions of the God-head without collapsing or conflating the processions into the missions in absolute terms (i.e. it honors archetypal and ectypal knowledge of God).
No subordination of the Son is entailed by his generation by the Father. There is certainly active and passive in their relation: the Father begets, the Son does not, but has his personal subsistence by virtue of the Father’s act. But the passive generation attributed to the Son, his being generated, is no less an ontological perfection than the Father’s active generation. Once again, generation and consubstantiality support each other.
At a relatively straightforward level, generation does not involve the Father’s temporal priority over the Son, because eternal generation is not temporal beginning. Begetting is ‘above all “when” or ‘beyond the sphere of time’. The Son is from but not after the Father. But this opens into a larger point about the Son’s perfect deity. In being generated by the Father, Hilary tells us, the Son retains ‘the fullness of that Godhead from which and in which he was born as true and infinite and perfect God’. This extends a point made earlier, namely that the relation unbegotten:begotten is of a different order from the relation creator:creature, since begetting is not making. The extension consists in denying the identity of being unbegotten with the divine essence. Gregory of Nazianzen pushes the point against opponents who claim that ‘if the Son is the same as the Father in respect of essence, then if the Father is unbegotten, the Son must be so likewise’. ‘Quite so’, he says, ‘if the essence of God consists in being unbegotten’. But it does not: ‘Unbegotten is not a synonym of God’. Unbegottenness is in fact the personal characteristic of the Father, not a property of the common divine essence; and so the Son’s being begotten does not exclude him from deity.
Using a slightly different idiom, Aquinas argues that to speak of the Father as principle (principium) is not to think of him as superordinate over the other two persons for principle means ‘not priority but simply origin’. This means that it is proper to speak of the unregenerate Father as ‘a principle not from a principle’, and of the Son as ‘a principle from a principle’ by virtue of his generation, without disturbing the eternal co-equality of Father and Son. In the terminology of post-Reformation divinity, the Son is still autotheos. He is this, not in respect of his person (which he has from the Father) but in respect of the common aseity which he has as a sharer in the one divine essence. The Father is a se in his person (as the principium of the triune life); the Son is a se only in his divine essence. ‘The Son is God from himself although not the Son from himself.’
In terms of trinitarian doctrine, this affirmation that begottenness is a divine perfection offers protection against what Tom Weinandy has called ‘emanationist sequentialism’: origin and order in the triune life are not a matter of ‘priority, precedence and sequence’. There is a proper reciprocity between Father and Son, in which the Father’s personal character as Father is confirmed and glorified by the Son. Certainly, the Father is a nemine, from no one; but he is not solitary, for he is the eternal Father of the eternal Son, and so ‘the Father is glorified through the Son when men recognise that he is Father of a Son so divine.’ In Christological terms, it reinforces the core conviction of Nicaea, that the ‘ek’ in ‘God from God, light from light, true God from true God’ does not alienate the Son from the life of God, and that the Son’s coming down from heaven is truly the presence of the perfect God.
In light of such sustained consideration one wonders how the evangelical contingent of ESS or EFS proponents can continue to live life unrepentant. I don’t expect them to repent, even if they were to read such eloquent consideration of such a beautiful doctrine as we find in the eternal generation of the Son in his utter begotteness. The unfortunate thing is that the evangelical’s commitment to constructing cultural idols (complementarianism, egalitarianism, etc.) is allowed to shape the conclusions of their biblical exegetical projects; which then makes their projects eisegetical. This is unfortunate because such voices have large places in the broader mainstream of the evangelical churches across North America and beyond.
You might be wondering why this ultimately matters. Because Christians are people of the truth, and we want to make sure the God we worship is the God Self-revealed in Jesus Christ (i.e. working out the inner-logical reality of that as far as we can) rather than one constructed upon social or other whims that end up hybridizing him thus turning him into a human projection rather than the God of God who he is for us.
I think many of these EFS proponents think they have out-lasted the social media or blog cycle, as far as attention span. Nope, some of us are still watching; we see you, and continue to call you to repentance. You are living in doctrinal sin, and thus have a root of theological sinfulness fomenting your life and ministries to and for others; and even for yourselves. We are still watching, and my five-hundred readers will continue to be made aware of your intentional sinfulness when it comes to this most important doctrinal consideration. So I say again: Repent!
 John Webster, God Without Measure: Working Papers In Christian Theology: Volume 1 God And The Works Of God (London-New York: Bloomsbury T&T Clark, 2015), Loc 839, 848, 857, 866 kindle version.