We Protestants have inherited from the Reformation the very praise-worthy desire to be continually about the work of reforming our churches to bring them into line with the Scriptures. That covers all sorts of areas of church life - liturgical, ethical, governmental. It also covers, I take it, theology. We want to be continually examining our doctrine in the light of Scripture, and we certainly intend to be prepared to change our doctrine to conform it more closely to the word of God.
On the other hand, we have inherited from the period directly after the Reformation the praise-worthy desire to defend the gospel from attack and misunderstanding. It is to this desire that we owe our great confessions, documents designed to set out the truth in summary form. These documents to a certain extent codify what is to be believed if one is to be considered faithful to the gospel.
It is not hard to see how these two desires could come into conflict. What happens when you become convinced that the 'traditional' way of expressing things is not entirely in line with Scripture? The great confessional statements very easily become badges of identity and litmus tests of 'soundness' - to the point where simply using different words (even if in material agreement) can place someone beyond the pale.
How do we make semper reformanda a reality in the realm of doctrine without cutting loose and letting anyone say what they want? How do we maintain confessional standards without shutting ourselves off from the word of God?