For example, here is a beautiful illustration of Luther on the froehlich Wechsel, or "joyful exchange" model of salvation:
Christ is full of grace, life, and salvation; the soul is full of sin, death, and condemnation. Let faith step in, and then sin, death, and hell will belong to Christ, and grace, life, and salvation to the soul.
For, if [Christ] is a husband, he must needs take to himself that which is his wife's, and, at the same time, impart to his wife that which is his. For, in giving her his own body and himself, how can he but give her all that is his? And, in taking to himself the body of his wife, how can he but take to himself all that is hers?We may steal this outright on Sunday.
Beneath this image lies, of all things, Song of Songs 6:3 and related passages. It takes the Biblical image of the Church as a the Bride of Christ and personalizes it, applying it to the spiritual life of each individual Christian.
This is a sharp contrast to the "commercial" model many of us (including Fr. A.) have been taught. In that model, human sin creates a debt to God, which is paid for each of us by the merits of Christ. The only real difference between Luther and his opponents, in this view, is whether the Church has the power to move these merits around like so much cash in a counting-house, or whether that power is exercised exclusively in Heaven.
As Paul Hinlicky pointed out at our last synod assembly, the "commercial" model is, like the "forensic" or legal model beloved of the Gnesio-Lutherans, profoundly impersonal. The movement of merits, like the judicial judgment, takes place somewhere else, far from us. We are saved or damned in absentia. But to speak of salvation as a marriage, albeit between parties of vastly different stature, is inherently personal. Our exchange of wedding gifts can only take place only as the result of an intimate personal encounter -- indeed, the most intimate and most personal encounter. (Insert here your own giggly allusion to Bernini's Santa Teresa).
One might not want to go too very far with this language. Marriage, as it was known either in antiquity or in the Middle Ages, had a side that may seem sordid to us moderns. Brides, in particular, did not always enter into it of their own will. Within marriage, women lost some of their identity and, not infrequently, claim to much of their property. Love was an ancillary consideration, especially among the upper classes.
Still, we are enchanted by this idea, and plan to run with it for a good long while.