Admittedly, in some ways, Lutheran theology can seem quite individualistic – obsessed with “private judgment”, some say. Like the Enlightenment philosopher Immanuel Kant (himself of Lutheran Pietist origins), Lutherans seem to be good at “hav[ing] courage to use [their] own understanding” (of course Christians have been known do this: “I believe in God the Father Almighty…”).
This tendency of Lutherans becomes especially clear when we closely examine their ecclesiology. Most serious-minded Lutherans insist that we simply cannot see the Church in terms of individuals who “find themselves to be united with one another”. At the same time, these serious Lutherans nevertheless seem to encourage – even require – the certain belief that one, as an individual, has saving faith (i.e., they are in a state of grace). Others? Only God ultimately knows.
Can this be right? Is this the faith of a child?
First of all, this presentation is not as nuanced as it should be: the belief that one has saving faith is really a form of reflective faith (faith thinking about itself, i.e. a believer’s conscious reflection on their belief) – this is inherently unstable, due to the persistence of original sin (for we never believe as trustingly as we should, and hence, reflection will lead to accusation by the law!), not the basic, simple, child-like, direct faith that actually trusts and grasps Jesus Christ’s promise of forgiveness, life, and salvation in real time. Believers are first and foremost certain in regards to the life-giving Promise God continually gives them in His great mercy – in spite of their sin (i.e. “Love to the loveless shown that they might lovely be”). In other words, children – even infants – simply receive this confidence and surety sans reflection: it is a “pre-rational trust”.
Second, although for the most part, we assume – or should assume – that those in fellowship with us receive and recognize the Promise as we do, there is a good reason we can’t be as sure about their relationship before God (or anyone outside of our fellowship for that matter): the Scriptures reveal that when it comes to identifying true Christians (as opposed to true Churches / doctrine) God knows who are His, while we, noting Jesus’ parables about the Kingdom of God, must discern (judge) by externals… by what we see… by fruit… (and here, regarding “fruit”, what a person confesses with their mouth [Rom 10] in regard to God and His teachings are in view as well as behavior – see the end of Matthew 13, for example).
Of course, the evidence this fruit offers us is not worthless, for the Apostle Paul would not say he is persuaded the faith of Timothy’s grandmother lives in him and Jesus would not say that “wisdom is proved right by her children” if this were so. Yes, the same child who trusts Christ likely does not think to question the faith of the one who shares Christ with him, but as faith matures (growing in the aspects of “assent” and “knowledge” in addition to “trust”) and takes on “the whole counsel of God”, the wise believer, using evidence and intuition, will often be “persuaded” he is dealing with a person who truly has genuine faith (even as we are only called to consider those in baptized fellowship with us to be “truly Church”) – as even those with the strictest views on Church fellowship acknowledge.
And yet, there is nothing greater than the certainty – the knowledge of eternal life – that the received Promise creates in the individual believer. Here of course we are not talking about mathematical certainty, or that certainty which can be derived from axioms or discerned patterns (based on repeated experiments and observations), but rather personal certainty, personal knowledge – knowing a Person. And borrowing the language of law courts, one may believe that one’s parents truly love them “beyond a reasonable doubt”, but the Promise brings us into a realm beyond even that – into the realm of a loving and secure relationship that exists “beyond a shadow of a doubt”.