Yet another implication of the concept of ‘canon’ is that of limits of belief. These limits take on a variety of forms, but all Christian Bible readers submit themselves to limits in one form or another. Christians ever since the time of the apostles have recognized that the Bible teaches certain truth claims but not others. For example, the Bible has always been understood to teach that it was the God of Abraham, Isaac, and Jacob who created the universe, not some other god. These truth claims that form the Christian faith were called the regula veritatis (rule of faith) by Irenaeus of Lyons, who wrote as early as 180–190. Various alternate forms of this phrase were quickly taken up by Clement of Alexandria (c. 200) and Tertulian of Carthage (c. 210). Since this time, Christians have not ceased to make confessions, creeds, and doctrinal statements that define the Christian faith and practice. These statements are, in essence, a big picture of what the Bible teaches and what it means to be a Christian. They outline what the Bible must teach. For example, whatever the Bible teaches it must teach that Christ is the son of God, who is the same God of Israel, of Abraham, of Isaac, and of Jacob. It is in this way that rules of faith both define the Christian faith and delimit the teachings of the Bible.
Understandably, the notion of an authoritative statement governing the content of one’s interpretation creates anxieties for many interpreters. These objection arise from the fear that such statements stifle objective interpretation; such statements are seen as the worst part of ecclesial authority in pre-modern biblical interpretation. On the other hand, these statements are effective at distilling the mass of biblical content into its most essential elements. As Moberly argues,
“The point of a rule of faith, and related notions, is not to deny that the Bible can legitimately be read for purposes other than those of faith, or to pre-empt the question of how what Scripture says is best understood if the plain sense of the text appears to be at odds with traditional ecclesial formulations or with Christian moral values. Rather, one primary point of a rule of faith is the need to have a picture and construal of biblical content as a whole — which, given the diversity and complexity of biblical content, is no easy matter.”
According to Moberly, these rules of faith, and similar statements, should put Christians at ease not create anxiety. Rules of faith, far from stifling different interpretations, are often so broad that they allow for healthy diversity. In short, the Bible as ‘canon’ means that Christians should read the Bible confidently knowing that they can read and interpret the Bible meaningfully.
 Ibid., 121.