Quote from : Scripture Alone: Exploring the Bible's Accuracy, Authority, and Authenticity Book

The guiding factor for the development of Christian doctrine is the Bible itself! The text of Scripture provides the grounds and, most important, the limits for this development over time. Rather than bringing in outside influences (such as tradition), we recognize that no one has ever plumbed the depths of God's revelation contained in Scripture; no one has ever come close to exhausting what is to be found in its pages. Therefore, real development of Christian doctrine is simply our ever-increasing understanding of the Word. It is a delving deeper and deeper into the truths of the Word.