Rule of Faith: The set of standards that define a religion. Protestants hold to Sola Scriptura (“Scripture alone”). Catholics and Orthodox use Scripture and Tradition (there are differences in understanding and application of that tradition).
Related Concepts and/or Examples
Tertullian on the Rule of Faith – origin of the phrase
How Important is Sola Scriptura? – from the Arminian perspective
John Wesley on the Bible – how the founder of Methodism understood the Rule of Faith
Irenaus on the Rule of Faith – precursor to Tertullian
For all entries in the 31 Days of Feasting on Theology series, go here.