A Roman Catholic page
has a surprisingly accurate summary of a key difference between Lutheran and Reformed (including American Protestant) doctrines of assurance
. Which of the following promises by a groom would elicit his bride's trust?
1. "I will love, honor, and cherish you." (She simply believes him.)
2. "I will love, honor, and cherish you if you really believe this promise with sincere faith." (She must not only believe him, but must also believe in her own belief. Must she then believe that she believes in her own belief?)
The first promise would be like that of the gospel as represented in the Lutheran confessions, especially in the Solid Declaration of the Formula of Concord (Article 11, paragraphs 70-75):
“The certainty of being elected can be based on nothing else than the certainty of faith itself, namely, on the Person and the work of Christ. Accordingly, those who are troubled with regard to their election are to be referred to the means of grace, to Word and sacrament, in which the promise of the Gospel is offered to them, but not by any chance to ‘what they find in themselves,’ namely, to their ‘piety and virtue,’ which they Spirit brings about in the elect. At this point the divergent position of Calvinism with respect to the idea of predestination becomes most clearly apparent from a practical point of view. If the question whether one is elected diverts one’s view for but a moment from Christ to the ‘fruits of faith,’ then one has gone back almost precisely to the doctrine of certainty which Luther attacked and which resulted in his book. It is true that that Formula of Concord, in conformity with the Biblical direction, admonishes believers ‘to make sure,’ by practicing all virtues ‘that they have been called and elected, in order that the more they find the Spirit’s power and strength in themselves, the less they may be in doubt of this.’ But the context teaches that it is by no means the purpose of these words to designate one’s own moral quality or accomplishments as the reason for the certainty of election. No, shortly before this the person in doubt is unambiguously referred solely to the Word of Christ. In addition to this, it is stated: ‘According to this teaching of His, they should desist from their sins, repent, believe His promise, and rely wholly on Him; and because we are unable to do this of ourselves by our own strength, the Holy Spirit wants to work this, namely, penitence in faith, in us through the Word and through the sacraments.’ ...the idea of making sure objectively of election cannot be interpreted synergistically. When, therefore, the elect ‘find the power and strength of the Spirit in themselves,’ this can contribute toward the overcoming of doubt only when attention is actually directed to the power of the Spirit, who is operative in the Word. This is amply confirmed when it is stated further: ‘And even though they perhaps come into such deep trouble that they think they no longer feel any power of the indwelling Spirit of God... then, in spite of this, they should say again with David, regardless of what they find in themselves: ... ‘Nevertheless, You hear the voice of my supplications.’” [Elert, W., The Structure of Lutheranism: The Theology and Philosophy of Life of Lutheranism Especially in the Sixteenth and Seventeenth Centuries
; Concordia Publishing House: St. Louis, Missouri, 1962, pp. 135-136, parenthetical phrases removed, English updated.]