Not too long ago I made a post about various analogies for the Trinity given by many ancient and medieval Christian authors. I’ve also come to realize that something very similar is going on in 1 Corinthians 2:
It is of the mysterious wisdom of God that we talk, the wisdom that was hidden, which God predestined to be for our glory before the ages began. None of the rulers of the age recognised it; for if they had recognised it, they would not have crucified the Lord of glory … to us, though, God has given revelation through the Spirit, for the Spirit explores the depths of everything, even the depths of God. After all, is there anyone who knows the qualities of anyone except his own spirit, within him; and in the same way, nobody knows the qualities of God except the Spirit of God.
I find that this passage is remarkable for being such a condensed statement of the Orthodox doctrine of the Trinity. By stating that the rulers of the age “crucified the Lord of glory,” the Apostle recognizes Christ’s divinity and also undermines Nestorianism. By referring to the Holy Spirit as God’s “own spirit,” analogous to the spirit within each of us, St. Paul confirms that the Holy Spirit is likewise consubstantial with God, as our spirit is not identical to us but nor is it a different thing from us – and this, further, makes clearer how the Holy Spirit can be God without being the Father and without being another God, as later theologians would make more explicit.