Let’s begin with the basic reason why it is so important to understand what the ground of our justification is — the early Reformers insisted on this (rightly) in the Pauline spirit of preventing any man from boasting about his salvation, which sinful men always want to do. The point was not that we had to have every detail of God’s foundation worked out (which would be presumptuous), but rather that we understand that the foundation was not a mixture of iron and clay. The foundation of our justification cannot be partly God and partly us. If it is, then all of us are in deep trouble.
Now I am entirely in sympathy with the suggestion that the lifelong obedience of Christ, recapitulating the history of Adam, as well as the history of Israel, is the foundational to our glorification, just as the first Adam’s obedience would have been the foundation of our glorification (without have to expiate sin) had Adam only obeyed. So much is obvious. But given the intrusion of sin, and the reality of it, and the stark fact of the fall, we are more than justified (heh) in linking our justification and our glorification. Paul places them end to end like boxcars in Romans 8.
“And we know that all things work together for good to them that love God, to them who are the called according to his purpose. For whom he did foreknow, he also did predestinate to be conformed to the image of his Son, that he might be the firstborn among many brethren. Moreover whom he did predestinate, them he also called: and whom he called, them he also justified: and whom he justified, them he also glorified. What shall we then say to these things? If God be for us, who can be against us?” (Rom. 8:28-31).
Justification is on the way to glorification. It would not have been had Adam not sinned, but that is not the world we are in now. This means there are a couple of anomalies which prevent us (in my view) from applying the active, recapitualting obedience of Christ to glorification alone, and His passive obedience on the cross to justification alone. The first is the order in which they come in the life of Christ — which is to say, backwards. Why would the obedience that establishes glorification precede the obedience that establishes forgiveness, without which I cannot have glorification? It is out of whack typologically. It is as though Christ built the attic and then poured the foundational concrete on top of it.
The second anomaly is that in other circumstances, some FV advocates are comfortable in speaking of a future justification — speaking of the actual, final deliverance, the deliverdict. Although I don’t really speak that way, so long as terms are stipulated and used as defined, I can live with it and profit from it. But this means that justification and glorification are not being kept in separate places like they were oranges and bananas. Given God’s saving intention for a fallen race, they now are organically connected, and are all part of the same glorious inter-related process. But this means that the recapitulating obedience of Christ cannot be reserved apart for justification-at-the-moment of conversion alone.
All of what Christ did and accomplished is applied to all of what we need — and we need it all, all the time. And this brings us back to the first point. Our salvation, every aspect of it, owes its reality to solus Christus. And it must be solus et totus Christus — not only Jesus, but only Jesus and all of Jesus. This means that we are resting, not upon the essence of Christ, but upon the history of Christ, the biography of Christ, which, when rightly understood, is the history of the world. It is a new history, now being written on top of the old — in Christ we are God’s palimpsest.