Thanks to FWS who pointed us to this post from LCMS president Matthew Harrison quoting the German theologian and enemy of Nazism Hermann Sasse (who quotes Werner Elert):
Werner Elert repeatedly drew our attention to the fundamental difference between the Roman Catholic and Evangelical Lutheran understandings about ecclesiastical confessions of doctrine. It consists in this, that the Roman doctrinal confession has the form of an imperative, while the Lutheran has the form of an indicative. Roman dogma is a command of faith; the Lutheran an expression of faith. There, a credendum [something which must be believed] is presented with a command to accept it. Here is expressed, what the church [already] believes: “We believe, teach, and confess.” The difference is deeply-rooted in the concept of faith. Faith, in the Catholic sense, is the supernatural virtue, by the power of which I hold for true that which the church presents to be as the content of revelation. . . .
Thus the objectum fidei, the object of faith, is defined. Corresponding to the concept of faith as “holding something to be true,” the object of faith is, for a Catholic, always dogma, for example the dogma about Christ. Corresponding to the evangelical concept of faith as fiducia, as trusting the divine promise of grace in the gospel, is the fact that, for the Lutheran, the objectum fidei is not the dogma about Christ, but rather Christ Himself; not the dogma about the Trinity, but rather the Triune God; not the Bible as such, but rather God, Who speaks to us in each word of the Scripture.This important distinction was mis-used, by Ritschl and his school in his time, but then by the entirety of modern liberalism, in order to get rid of dogma in general.
Faith isn’t just believing that God exists. It means trusting God. Of course, God has to exist if we are going to trust Him–and the quotation goes on to show why “dogma” remains important–but just the truth claims are not sufficient. This explains why atheists keep missing the point and have little impact on evangelical believers. They keep belaboring the truth claims–“But there isn’t enough evidence!” “We can never know for sure!”–while being oblivious to what faith actually is to those who have it.