Why do we need anyone to defend the Christian faith?
And what must they defend it from?
Mark Rushdoony answered those questions in this 2014 essay.
Mark refutes the contention that the early church was “pure.” Good lord, no! As people throughout the Roman Empire joined the church, they brought all sorts of pagan ideas in with them. The church needed to call authoritative councils to weed out the paganism and state orthodox Christian belief as plainly as possible–which is why we have formal creeds.
We hardly need say that they’re still trying to import pagan notions, and humanist delusions, into the church (can you say “feminist theology”?). Because the church today is split into so many denominations, it’s no longer possible to hold a council that would speak with real authority. So we rely on the ancient creeds to protect us–and to keep us clear about what we believe.
Mark also provides a list of the major heresies the church had to deal with in the first centuries of its history. Most of them are still around, repackaged under new names. Well, that’s Original Sin for you. In a fallen world, we are always obliged to defend the Christian faith.