I remember the feeling when it clicked. I felt heat behind my eyes, goose bumps covered my arms and neck, my jaw dropped. I was listening to a lecture on 18th-century pastor-theologian, Jonathan Edwards’ End for Which God Created the World. The lecturer drew a diagram explaining Edwards’ doctrine of the Trinity. Nothing new, just sheer confusion.
He was talking about the fact that God did not have to create anything. He perfectly existed in complete aseity; that is, in need of nothing, entirely and eternally content and happy in himself. Such contentment is only possible because God is most basically Triune. This would not be the case if God was some ethereal, far off deity existing in complete and utter isolation in eternity. That kind of god would create out of necessity. Not so with a God who is already actively engaging and loving himself, among the three persons of the Trinity: Father, Son, and Spirit. This is the ad intra glory of God. That is, it is internal within the community of persons of the Trinity.
The lecturer went on to offer a solution to the question of, “then, why did God create?” He said that God loves himself, but God also loves the fact that he loves himself. Because himself is the single most morally perfect thing to love.
God’s love of the love he has for himself was such that it inclined him to share himself; that is, the Trinity. This is the ad extra glory of the Trinity; the glory which inevitably must emanate from such a fountain of glory. “Okay…?” was the general response of the class at this point.
And so, God created. But the lecturer did not stop there. He went on to revise his diagram of the Trinity, only this time he included the redeemed church in the discussion.
The class watched eagerly as he drew out his old, familiar diagram. Then he did something no one saw coming. Father, Son, Spirit he drew. Then next to ‘Son’ he drew a big slash and wrote ‘Church’.
That’s when it clicked. We hear over and over in Christendom that the redeemed are united with Christ. Really, it’s become a bit cliché. Not anymore. Union with Christ is not some nebulous concept; rather, it is true, unequivocal inclusion into his own family. All of the familial metaphors in Scripture suddenly made sense. The union between husband and wife “refers to Christ and the church”. Adoption makes us “co-heirs with Christ”. Rebirth makes us “children of God”. The Trinity is a family. And it is simultaneously entirely satisfied and happy ad intra while it is such that it inevitably expands and shares that satisfaction and joy ad extra.