However, given the context of which the synod seems (in this translation) to be speaking, they are right. Even the most fundamentalist Bible only Christian is not a “Religion of the Book” in that there are doctrines that are not explicitly spelled out that all Christians hold. For instance, while the Bible speaks of the Trinity and Incarnation, the details are pretty vague at times. But looking at the Scripture and thinking about it, you can get a better idea. In Islam, that would not be possible.
To say that the doctrine of the Triunity of God is most certainly Biblically derived and substantiated, and if the born again Christian faith was not that of the Book, and which materially provides pastors, etc., it would simply not exist.
(James 1:18) “Of his own will begat he us with the word of truth, that we should be a kind of firstfruits of his creatures.”
(Eph 1:13) “In whom ye also trusted, after that ye heard the word of truth, the gospel of your salvation: in whom also after that ye believed, ye were sealed with that holy Spirit of promise,”
(Rom 15:4) “For whatsoever things were written aforetime were written for our learning, that we through patience and comfort of the scriptures might have hope.”