When I was a seminary student, there was a lively book market on the campus. Books were our educational meat and drink, so book auctions were anticipated with some relish, and sales between students were not at all uncommon. I remember listening in on the negotiations between two students over a textbook in a required class just finished by the book's owner and a student who wanted the book because he was enrolled in the class in the next quarter. The haggling reached an impasse when the owner of the book insisted: "I won't take any more than ten dollars for this book." The buyer made a counter offer: "Look, I will pay you twelve dollars for it. Take it or leave it." With some glee, I injected myself into their negotiations, "You boys have it all wrong! Let me, the Canadian, explain the capitalist system to you Americans. The seller should be asking for more and the buyer should be offering less. Not the opposite." Both were haggling against their own economic interests; giving more and getting less. Who would do such an absurd thing?

Who would give more and get less? God. He gave His own dearest Treasure, His beloved Son into death for sinners like us. What kind of exchange is this? Hardly a capitalist exchange! It is an exchange of grace, what Luther calls the "blessed exchange." "I have that...blessed exchange by which I know that death has been changed into life, destruction into eternal salvation, and sin into righteousness" (Martin Luther, Lectures on Genesis, 35.3). This exchange is blessed to us because we would never merit its benefit using our own resources. Apart from God's grace, which substitutes the shining righteousness of Christ for our filthy sin, we would be so deeply damned that we could not even fathom the depth of our state. The only way we are going to be raised from liability to death and obedience to its king, sin, is by grace for we have not the resources within ourselves to do anything about it.

What does God get from us? Our sin and death, which is far worse than nothing. God does not forgive our sin and rescue us from death and the devil by mere caprice, as thought it were merely a random act of kindness on God's part. No, He lays upon the back of our dear Lord Jesus the things exchanged for the gifts of God's grace. Our filth, sin and death now are Christ's, and if so, they are no longer ours. So God gives holiness to the saints for Christ's sake and in exchange the saints hand over the burden of their death and sin. Christ becomes the infinitely valuable "voucher" as John Chrysostom says, becoming what we might call the gift card that just keeps on giving.