Fred Sanders is correct to argue that the first step in speaking about the trinity is not to establish the relevance of the doctrine. Rather, he argues for the reality of the immanent Trinity as the presupposition of the gospel, and the ground and origin of divine grace toward humanity and all created things. I particularly like his language of “God…in himself, at home, within the happy land of the Trinity above all worlds…”
The cry in our day always seems to be for a practical doctrine of the Trinity, for relevance, application, and experiential payoff. Indeed, it is true that the doctrine of the Trinity changes everything about Christian life. But the wisest Christian teachers have always known that shortcuts to relevance are self-defeating. In bypassing the deep sources of reality, they not only miss the truth but ultimately deliver less practical benefit. When it comes to the difference that the doctrine of the Trinity can make in our lives, it is crucially important that we begin with a recognition of God in himself before moving on to God for us. What we need to begin with is a profoundly impractical doctrine of the Trinity. With that in place, we can really get something done…
The Trinity isn’t for anything beyond itself, because the Trinity is God. God is God in this way: God’s way of being God is to be Father, Son, and Holy Spirit simultaneously from all eternity, perfectly complete in a triune fellowship of love. If we don’t take this as our starting point, everything we say about the practical relevance of the Trinity could lead us to one colossal misunderstanding: thinking of God the Trinity as a means to some other end, as if God were the Trinity in order to make himself useful. But God the Trinity is the end, the goal, the telos, the omega. In himself and without any reference to a created world or the plan of salvation, God is that being who exists as the triune love of the Father for the Son in the unity of the Spirit. The boundless life that God lives in himself, at home, within the happy land of the Trinity above all worlds, is perfect. It is complete, inexhaustively full, and infinitely blessed. (Fred Sanders, The Deep Things of God, 95, 62).