The next to last chapter of Piper’s book (not counting appendices) returns to the question of imputed righteousness.
The righteousness of God’s (His covenant faithfulness) caused Him to send Christ. But He didn’t just send Him, He also reckoned that His righteousness was ours in the same way that He reckoned that our unrighteousness was His on the cross.
Piper quotes Wright (referring to 1 Thess. 2:18-20) as saying this:
I am on the road, and just got back from a wonderful lunch with a group of very sharp seminary students from RTS in Jackson. We spent a good bit of time talking about these issues of imputation, and the active and passive obedience of Christ. If Wright is arguing with the merit paradigm, and he is rejecting it while using the language of imputation, I am sympathetic. If I may speak in a cryptic fashion, merit bad. Merit no good. So to speak. But the obedience of Jesus, all of it, is ours. Christ recapitulated the history of Israel in His life, and He did not do this as a type of typological doodling. There was a point — there was a need for it. Israel needed to do it right, and Christ as the new Israel did it right. This is nothing other than the good news of imputation. I needed to have that obedience, and now, by faith in Jesus who did have it, I do have that obedience.
But if Wright is rejecting more than the brownie points system, and is rejecting the idea of imputation itself, then I am with Piper. But I don’t know how Wright could be rejecting imputation itself — provided we define our terms carefully. Wright knows that Jesus recapitulates the history of Israel, only doing so in obedience instead of the old Israel’s disobedience. Since He was not simply amusing Himself, that recapitulation is ours. And if it is ours, it has to be ours by imputation, whether righteousness floats across a courtroom or not, and whatever you call it.
Why am I a sinner? It is because my covenant representative, my covenant head, disobeyed in the Garden. How did that unrighteousness get to me? It did so by covenant representation. The whole federal vision controversy boils down to this — the Latin word foedus means covenant. The original meaning of the word federal means covenantal. The federal vision constitutes an attempt to get Reformed Christians to see life (that’s the vision part) more covenantally. But covenant theology does not refer to God making countless covenants with countless individuals. He made one new testament, in which we all participate by faith. And when we participate in the covenant, we are united to the head of that covenant. When we are united to Him, all that He is, all that He has, and all that He has done, becomes ours. That is imputation, however we dance around, or whatever we call it.
Now, one of you will say, what about the reprobate covenant member? Is he united to Christ in the same way, in such a way that he enjoys the benefits of this imputation. No, of course not. The elect covenant member and the reprobate covenant member are not united to Christ in the same way, with duration being the only difference. There is a qualitative difference between them all along.
To summarize, anyone who believes that Jesus is a covenant head, anyone who believes that Jesus is the new humanity, anyone who believes that Jesus is the new Israel, believes in the imputation of Christ’s obedience, all kinds. And I am glad, because otherwise we should worry.