I think many issues arise mainly because transcendence is widely under-appreciated. A particular issue that has recently caught my attention is the supposed heresy of “adoptionism”. One place this comes up is in Hebrews 1:2-5; 5:1-10. Christ, as Son of God, was the agent of creation, from the beginning; yet He was appointed and begotten when He ascended to the right hand of the Majesty. These are the two sides of the paradox of the eternal pre-existing Son of God / Logos, who was also appointed and begotten after His resurrection, due to His obedience (or, alternatively, at His baptism). In order to preserve His full eternal deity, such adoptionistic statements are traditionally interpreted to mean merely His manifestation and revelation as the Son and the King, or the accomplishment of His specifically soteriological mission. I propose it is better to give full weight to both sides of this paradox, and not try to reconcile them within an analytical system of thought.
When speaking of deity, we are attempting to talk about that which transcends space and time. All analytical / conceptual thought, which depends upon space-time metaphors, is therefore inadequate. Any attempt to analytically reconcile such paradoxes will severely and unnecessarily distort the truths that are revealed in the simple assertion of the paradox. It is better to simply accept and embrace such paradoxes. We should consider eternity as including and embracing temporality, in that it transcends the conceptual distinction between eternity and temporality.
The particular paradox of eternal sonship being qualified by incarnation was addressed by Robert Jenson, in saying there is no Logos asarkos. The eternal Son, from the beginning, is founded upon the temporal life of Jesus of Nazareth. By extension, the entire creation, from the beginning, is in some sense causally dependent upon his life as a man. We should give full weight to this bottom-up Christology, and not compromise it for the sake of top-down Christology. I think this was an important point in Pannenberg’s theology. To honor what is revealed, we must fully accept each side of this paradox as equally valid partial truths. To do otherwise would compromise the full truth.
Another application of temporal transcendence is the doctrine of justification. Justification in the present is based on a future completed lifetime of faithfulness. This is because salvation depends upon participation in Christ, which is an eternal transcendent reality. Any attempt to reconcile all aspects of atonement within an analytical system will result in a distortion that fails to represent the full truth. It is better to live with the tension between the assurance of hope and the obligation to persevere: another teaching from Hebrews.
Similarly, there are paradoxes related to space and spatial relationships. The unity of all things, in One, transcends the diversity of the many in space, but in a way that embraces and includes the spatial diversity of the many. This would apply to the paradox of corporate versus individual identity, and the related doctrines of unity and participation in Adam and in Christ. The answer, again, is to accept the paradox.
Such observations also apply to the more general disputes about open theism – whether God is permitted to be mutable and passionate – for the non-contingent God to be partly defined by the contingent creation. This further relates to the distinction between the immanent Trinity and the economic Trinity. We can and should accept that the immanent Trinity includes and embraces all that can be said about the economic Trinity; what we say about the economic Trinity should therefore be accepted as fully valid, but partial, truth. Perhaps this is what Karl Rahner meant to say. The transcendent God is both passionately responsive and steadfastly dependable, even though systematic thinking sees it as paradoxical.
To state it more generally, transcendence transcends even the concept of transcendence. On difficult subjects like this, I often ask “what would Kierkegaard say?” In this, I think he would concur.