Imagine a couple standing before the altar on the day of their wedding. When they reach the point of the vows, instead of declaring their promise to be faithful to one another -- "for better for worse, for richer for poorer, in sickness in health" -- they lay down an ultimatum: "You had better love me and respond to my affection, otherwise I will not love you, and our relationship will never grow..."
Such a statement may actually be true, in a descriptive sense. In any faithful relationship, two parties ought to respond to one another in mutual love. For that husband and wife, in their relationship with one another, such a description would not be incorrect. But in that moment, what is really called for? Could such a statement really be called a "vow"?
Likewise, when we as Christians think about what is happening in worship in confession and absolution, the same questions could be asked. Are the words we use to declare absolution a description about forgiveness, or do the words actually declare Christ's forgiveness to the listeners? If it is not the latter, we need to ask ourselves: have we really delivered the promise?
In the Small Catechism, Luther rightly described the "Office of the Keys" as "that authority which Christ gave to his church to forgive the sins of those who repent and to declare to those who do not repent that their sins are not forgiven." Luther's description was written as instruction about how God's forgiveness works. The statement is succinct and accurate, based on Christ's own description of the authority He gave to His disciples (John 20:23, Matthew 18:18). Luther's statement, however, is not in itself a declaration of absolution.
One must read further in the Catechism to find where Luther provides an example of what the words of absolution might look like. A little later he writes: "The pastor may pronounce the absolution by saying, 'by the authority of our Lord Jesus Christ I forgive you your sins, in the name of the Father and of the Son and of the Holy Spirit.'" In contrast to the statement above, these words are not simply a description of forgiveness; they are an actual declaration of the promise of forgiveness in Christ. The words are a vow from God Himself.
When words of absolution are to be proclaimed, that is what is called for.
To be sure, when people gather for worship to hear the word of God, there are many opportunities for a preacher to describe the promise of God and to explain how the Gospel works. Knowing that God's second use of the Law (accuse and convict sinners) is able to work upon a listener's heart, the pastor has opportunities, through instruction and conviction, to help prepare the congregation to hear the Gospel promise. But when the promise itself is declared -- especially within a rite that refers to the declaration as "forgiveness" or "absolution" -- the preacher must come across with more than a mere description. Forgiveness itself must be announced, without condition, as an unadulterated promise from God, for the sake of Christ and by His authority.
Only by declaring God's vow to us, does Christ build the relationship that He has described. Only by the pure declaration of His faithfulness, do we humans come to trust and believe in Christ alone.
". . . just as Christ loved the church and gave Himself up for her, in order to make her holy by cleansing her with the washing of water by the word, so as to present the church to Himself in splendor, without a spot or wrinkle or anything of the kind -- yes, so that she may be holy and without blemish." (Ephesians 5:25-27)