The analogy of faith was a key principle of interpretation taught by the Reformers which which teaches that Scripture should interpret Scripture. This principle is stated in the Westminster Confession (1.9) in this manner: "The infallible rule of interpretation of Scripture is the Scripture itself: and therefore, when there is a question about the true and full sense of any Scripture (which is not manifold, but one), it must be searched and known by other places that speak more clearly."
"There must be a consistency in all revealed truth because it represents absolute truth in the mind of God. Therefore each passage can have only one certain and simple sense. As the infallibly inspired word of God, the Scriptures are reliable, self-consistent and carry within them all that is needed for clarity. Since all that God makes known fits with what He knows perfectly, it is always proper to assume that no contradictions or dual realities can be attached to what He speaks." Bob Burridge
Charles Hodge, in his Systematic Theology, has expressed the idea this way: "If the Scriptures be what they claim to be, the word of God, they are the work of one mind, and that mind divine. From this it follows that Scripture cannot contradict Scripture. God cannot teach in one place anything which is inconsistent with what He teaches in another. Hence Scripture must explain Scripture. If a passage admits of different interpretations, that only can be the true one which agrees with what the Bible teaches elsewhere on the same subject.^^
Basis for the term
In Romans 12:6 Paul says that each one was to exercise his gift of prophecy, i.e., of teaching, "according to the proportion of faith." The Greek word for proportion here is analogia, and hence the phrase analogy of faith. The meaning is, that the utterances of the "prophet" were not to fluctuate according to his own impulses or independent thoughts, but were to be in accordance with the truth revealed to him as a believer. Following the Reformation, this phrase was used to mean that all Scripture was to be interpreted with reference to all other Scripture. In other words, no single text or expression of Scripture was to be isolated or interpreted in a way contrary to its general teaching.
Cautions and concerns
The principle of allowing Scripture to interpret Scripture is a valid aspect of the "analogy of faith," presupposing a unity and self-consistency in Scripture as the work of God. Critics from within conservative evangelicalism warn of potential misuse when the analogy of faith is restricted to that which one finds harmonious and non-contradictory at the expense of sound hermeneutics and exegesis.
Walter Kaiser, in Toward an Exegetical Theology, says "the Church at large (since the time of the Reformers especially) is in error when she uses the analogy of faith (analogia fidei) as an exegetical device for extricating meaning from or importing meaning to texts that appeared earlier than the passage where the teaching is set forth most clearly or perhaps even for the first time" (p.82). While the concept of progressive revelation suggests interpreting the Old Testament in light of the New, Kaiser argues that this is not a license to read meanings into the OT that are not there. He sees misapplications of the "analogy of faith" in the past doing just that.
Daniel Fuller also sees the use of the "analogy of faith" by the Reformers, evident in Luther, as introducing a subjectivity that sometimes contradicts the very idea of Sola Scriptura for which they argued (see Fuller, in external links below).
- ? Charles Hodge, Systematic Theology, Vol. 1, Introduction, Chapter VI, The Protestant Rule of Faith.