I found the following extracts helpful, particularly in relation to discussions about the ‘eternal subordination of the Son’.
The reason we know the Father-Son-Holy Spirit distinction is because the Father sent the Son and the Holy Spirit. The distinctions among the three persons were revealed in the act of the Son and Spirit coming to be among us for our salvation. The Old Testament may be full of hints and foreshadowings and resonant suggestions, but it is not full of clear statements that the one God is Father, Son, and Holy Spirit.
But the Father-Son-Holy Spirit relation pre-exists the sending of the Son and the Holy Spirit. God was Trinity before showing it.
The Father-Son-Holy Spirit relation is essential to the being of God. Unless God changed in essence in between the OT and the NT, the one God of Israel must be the Father, Son, and Holy Spirit.
If triunity is true now, it must always have been true.
The Father sent the Son in the fullness of time, by grace, because the Father is the source of the Son in eternity, by nature. This eternal relation of fromness has traditionally been called eternal generation.
Christians have always confessed God as Trinity, and they have always done so on the basis of the biblical doctrine of eternal generation.
The doctrine of the Trinity suffers equally from flattening out the distinctions among the persons and from over-drawing them. This is true in all epochs of trinitarian theology, but in our age, whenever trinitarianism is drawn into the orbit of gender politics we have two poles: An egalitarian round-dance of mutual affirmation by the anonymous three in their perichoretic commune of blissful sameness on the one hand, and a hierarchical committee in which the lower members are strictly observant of the proper channels for carrying out the deliverances of the senior members on the other. Okay, nobody’s doctrine of God reaches these extremes. But we seem to feel the pull of the poles. And we can tell which extreme any particular theologian most dreads by whether they feel reassured by adding or subtracting hierarchy.
1 Cor 11:3 is not a shortcut. It’s a bona fide hard passage, but mostly it’s about the incarnation.
Connecting Trinity to gender roles is a dangerously distracting pedagogical gambit.
Imitating the Trinity as Trinity is not a biblical way of talking. We are told to imitate God the Father in his relationship to humanity; to be imitators of God as beloved children; to be perfect as our Father in heaven is perfect (sending his rain on the just and the unjust). But most of the equipment of trinitarian theology points to ways in which God differs from us, not ways in which God is like us.
Unless social trinitarian impulses are carefully aligned with God’s utter oneness, disputes about eternal functional subordination are the least of the problems we should expect to arise.
It is hard to talk well about the Trinity.
There is a reason trinitarian theologians are cautious in their speech, and that reason is the extreme difficulty of doing justice to these matters without misleading hearers. The Trinity is about persons in relation in a certain taxis, not about people in relationships with certain roles. What is the difference between persons and people, relations and relationships, taxis and roles? We should talk about that. But notice that every time you say “three persons” instead of “three people,” you are registering in ordinary language your sense that the matters on the God side of the equation are high and lifted up.