Theologians have often used the term “grammar” to refer to the vocabulary necessary to speak correctly about one doctrine or another. This is especially true with respect to the doctrine of the Trinity; this most important, most studied, most clearly defined doctrine has been passed down to us using particular terms that have particular content (and exclude other content). Included in this Trinitarian grammar are a number of important distinctions, ones that help us talk about the Trinity in a biblically faithful and dogmatically precise way. The list below is not exhaustive, but merely a foray into how the Church has rightly divided Trinitarian grammar for the last two millennia.

1. Common & Proper. This is perhaps the most fundamental distinction, between what is common to the three persons of the one God in the divine essence and what is proper – unique – to each person. In classical Trinitarianism, the only characteristic proper to each person is their mode of subsistence in the divine essence. The Father is Unbegotten, the Son is eternally Begotten of the Father, and the Spirit is eternally Spirated from the Father and Son.
2. Creator & Creature. This is the other fundamental distinction in Christian Trinitarian thought; what is properly (uniquely) predicated of a creature cannot be predicated of the Creator or vice versa. (This is a crucial distinction when it comes to the Son’s submission to the Father.)
3. Immanent & Economic. The former refers to God’s existence apart from creation, including his decree. The latter refers to God’s existence, and particularly how the three persons of God relate, in the entire act of salvation, including the decree.
4. Immanent & Transitive. These two terms refer to God’s action, the former referring to his internal activity – activity internal to God’s being, i.e. the eternal relations of origin – and activity external to God’s being, i.e. creation and redemption. While God’s action is one, and while both of these actions are therefore eternal, it is important to recognize that immanent activity is necessary and external activity is contingent.
5. Necessary & Contingent. And that is the last distinction to be made (at least for this post). God’s immanent activity, namely the eternal relations of origin, is necessary for his being. It is just who he is. God’s contingent activity, though, the action of creation and redemption, is external to him, i.e. not necessary to his being. God does not have to take this action, and so whatever kinds of additional predications can be made about the relations that exist between the three persons in this external activity, they are contingent realities in God’s life, not necessary ones.

As you might imagine, the latter two distinctions have important implications regarding ERAS/ESS/etc. First of all, the distinction between necessary and contingent means that we cannot predicate of God’s immanent life what is only true in the contingent activity of creation and redemption. So, while some have pointed out that the Son submits to the Father in the covenant of redemption (if you accept such a doctrine), because that is part of God’s eternal but contingent activity, it is not appropriate to predicate an immanent submission of the Son to the Father.

Second, the distinction between immanent and transitive action is incredibly important. If God’s nature and his immanent existence include relations of authority and submission, that kind of relation necessitates transitive action. In other words, submission requires some external decision and activity in which one party submits to the other. This seems to undercut either the doctrine of aseity – God would be required to act in this case in order to be himself – or the eternal continuity of God’s being – God would change in his nature at some point (in his activity) and introduce a new kind of relationship in his immanent life.

These are the kinds of dogmatic questions I and Luke, among others, have continued to allude to in our posts about the Trinity and in subsequent public conversations. It is not enough to simply say that human father and son language in Scripture almost always includes an element of submission; one must also ask whether predicating what is true of human relationships of relations in God’s inner life is appropriate given these dogmatic considerations. I’d say the answer is, clearly, no.