Let's start at the very beginning, a very good place to start...
Way back in the misty recesses of the past there was a man named Vincent of Lerins, a Christian Theologian. He has come to be associated with a test for ecumenical orthodoxy known as the "Vincentian Canon". In this case, canon mean ruler, like a yard stick. A standardized tool for measuring things. What was Vincent's measuring stick to determine right Christian belief and worship??? This confounding phrase: A Christian ought to believe (as Orthodox) what has been believed by all Christians everywhere and always. Well that can be a difficult thing to nail down. If we look at a rendering of the Christian Family Tree, we see there are many branches of belief...
In John's Gospel, Jesus says "I am the vine, you are the branches" (John 15:5) As the body of Christ, we trace our story, our roots, our source to Jesus. As the church grew and expanded across the globe with multiple languages and cultures, cherished beliefs diverged.
One way to think about this great big family of God is as a common trunk (Jesus) with three main branches: Eastern Orthodox, Roman Catholic, and Protestant. Most expressions of church can trace their heritage through one of these main branches, and all are connected to Jesus. Building upon this common history, what can we identify as the things we all hold in common at a minimum....what C.S. Lewis called a "Mere Christianity". What are the basics, the non-negotiables? In a word, Orthodoxy.
(Orthodox Patriarch of Constantinople Bartholomew I, Pope Francis, Archbishop of Canterbury Justin Welby)
The fundamentals of the faith were attended to by the early Christians, and especially by the bishops of the world-wide church, for the first several centuries. There were three main offices in the church: Deacons, Priests/Elders, and Bishops. The Bishops were charged with the responsibility of the teaching office. They communicated "This is the Christian faith, that is not" to the rest of the body of Christ. They were overseers of the world-wide communion. This word, world-wide, has a greek root. In english, we say Ecumenical, in Greek it is Oikoumene. It means the 'inhabited world'. Oikos, is the New Testament word for household. The Bishops were holding in communion the Christians all over the inhabited world in one household. Greek was the dominant language in the East. In the West, the dominant language would become Latin. The word for the universal church, the whole body, would be catholic. This is distinct from Roman Catholic, but it bears a similar meaning. So, for almost a 1,000 years there was a church that believed the same basic foundational stuff (orthodox) as one body (catholic) all over the world (ecumenical).
Bishops from all over the world came together 7 times from 325 A.D. to 787 A.D. What they discussed were the fundamentals of true belief and praise for the Christian church. There were three topics that we're considered basic: 1) God is Father, Son & Holy Spirit (what has become known as Trinity), 2) The Incarnation (Jesus is God, the second person of the Trinity, and put on flesh and became truly human for us and for our salvation), and finally 3) salvation by grace. Eastern Orthodox, Roman Catholics and most Protestants all hold these basic beliefs in common. If people diverge from these basic beliefs and taught others to do so, the early church called them Heretics. The heretical made a choice to believe and teach things that were contrary to basic Christian doctrines (teachings).
Next time we'll talk about what the Holy Spirit helped the church discern at those 7 ecumenical councils, that Christians hold as fundamental to the faith.