To say that Father, Son, and Spirit are consubstantial is to affirm that each has what is necessary to count as fully and equally divine. They are not identicals, nor are they an absolute numerical unity, for at the level of persons, hypostasis, and relation, they are distinct. Plurality must always norm consubstantiality in this way. Nevertheless, the persons are not divided into distinct substances. Consubstantiality does not mean that the persons are fully distinct, individual instantiations of the same secondary substance or of a common genus. The consubstantiality of the Father, Son, and Spirit is a dogmatic presupposition of the claim that the Son and Holy Spirit are the self-revelation of the Father, mediators unlike any others. Consubstantiality also follows from the trinitarian nature of Christian worship, since only God is worthy of worship but recognition and worship of God as Father requires worship of the correlative Son and Holy Spirit. Here again, consubstantiality is normed by divine plurality, for the definition of God, what it means to be God, is to be Father, Son, and Holy Spirit. There is no God the Father apart from the Spirit and Son, no God without his breath and reason. We must regulate the unity we affirm in proclaiming divine consubstantiality through an equal affirmation that this unity is not one that destroys the distinction in hypostases. In other words, plurality in the Godhead regulates our initial affirmation of unity, just as the unity of the divine nature will help us clarify our initial steps toward speaking of divine plurality, as we will see in the next chapter. A denial of consubstantiality is a denial of the Trinity, but an affirmation of the consubstantiality of the Father, Son, and Holy Spirit is not yet a full affirmation of the doctrine of the Trinity.

D. Glenn Butner Jr., Trinitarian Dogmatics: Exploring the Grammar of the Christian Doctrine of God, 43-44.