You may know that I (sporadically but vigourously!) bang the drum for Christ the eternal Mediator being the deliberately revealed, consciously known object of faith in the Old Testament. Here are some posts on the issue.
By way of some kind of response, here are ten propositions that circle around some of the issues. (Fabricius eat your heart out).
For those yawning right now, hold on for some grand hilarity next week - I'm on holidays and will post only frivolity. For those fixing to flex their theological muscles, remember to play nice.
4. The trinity is not a proposition to be revealed about the living God. Trinity is not one more truth among other divine truths. Trinity is who He is and the dynamic by which all revelation occurs.
In that sense the NT doesn't reveal the trinity either. There's no Romans chapter 17 on the homo-ousios. I can't think of any Scriptural statements used in trinitarian discussions that are actually consciously addressing God's ontology. That is, there is no ‘And now about the divine nature, how can some say that God is only one Person, for clearly He has His being as a communion of three Persons.' Etc etc. We believe in trinity because God from God has encountered us in His revelation and promised His Spirit etc etc. Trinity is not one more thing about God, trinity is who this God of the Gospel is. Trinitarian theology is simply a reflection on the ways and works of these Three who are the one God.
An OT saint is just as well placed to reflect on the multi-Personal revelation she has been given. The data of multi-Personal revelation is there in both testaments. The co-ordination of that data requires a multi-Personal doctrine of God in both testaments.
Would Moses have articulated trinitarian theology in the language of Nicea? No. But neither would Peter. Nonetheless the God about Whom Moses wrote was the Unseen God Most High, revealed in His Angel who is the face-to-face LORD, and who fills His people with the Spirit of the LORD. Without such a doctrine the revelation of Moses, even on its own terms and in its own context, does not make sense.
In this way, the trinity is revealed in the OT in the same way it is in the New. As the work of the Three is unfolded in divine encounter so the presupposition of trinity is unavoidable.
My position is not basically that the proposition 'God is triune' is a known proposition in OT times. And the counter to my position is not 'God is triune' is too advanced a proposition for people in that stage of redemptive history. My position is that God is tri-Personal down to His bootstraps (to be terribly anthropocentric!) and unavoidably so in all His interactions with His world. Any honest reflection in any age on His character and being must conclude that He is indeed tri-Personal. Any reflection on His being that fails to see this, fails to understand this irreducibly triune God.