The regula fidei (Irenaeus, Tertullian) was a flexible summary of the gospel's main points — one God, Father, Son, and Spirit; creation; incarnation; resurrection. It functioned as a guardrail: any reading of Scripture that broke the rule of faith was reading it wrongly. The creeds later crystallized it.
Authority & Sources
Rule of Faith
nounThe early Church's summary of core apostolic teaching, used as the lens for reading Scripture rightly before the creeds were formalized.
Also called: regula fidei