Kota Honjo: Tertullian’s Theology based on "the Rule of Faith" (Regula Fidei)

Tertullian is noteworthy among the Church Fathers. In particular, as the first Latin Church Father, he had a great influence on the world of Christianity. As a Christian writer, he faced Roman society and his opponents, and he built the foundation of the Christian faith through his writing activities.Is it possible to detect any large theological changes between the early and late writings from the 31 extant works? Or is there a consistent theological foundation? This paper takes the position that the core of Tertullian's theology is "The Rule of Faith" (regula fidei).Tertullian converted from the Catholic Church to Montanism, and it cannot be denied that his theology also changed. In particular, many scholars are in agreement regarding ethics. However, during both his Catholic and Montanist periods, it is a fact that Tertullian used "The Rule of Faith" as his core theology. Moreover, it can be seen not only in doctrinal matters but also in ethical matters."The Rule of Faith" is a church tradition passed down from Jesus Christ to the apostles, and from the apostles to the church. For Tertullian, the person holding this is a true Christian in terms of both doctrine and morals. Tertullian could defend Christianity, discuss the doctrine problem, argue with opponents, and discuss ethics problems because "The Rule of Faith" was at the core of his theology. His argument was consistent. Thus, as the first Latin Church Father, Tertullian could construct his status as an authority.