Religion
In reply to the discussion: What Do Most Christians Believe? [View all]MineralMan
(151,928 posts)define their religion as they choose to. Those two creeds lay out the basic beliefs of a majority of Christians, actually. They've been used for centuries to define what Christians believe.
Some claim that Atheists try to define Christianity. We don't, as a rule. We simply look at the definitions provided by those who follow that religion.
Now, not all Christians use those two creeds to define themselves, but a majority does. The Roman Catholic Church uses one of those creeds. It is the largest denomination of Christianity. Mainstream Christian denominations also use one or the other of those creeds, with minor modifications, to define their basic beliefs.
Christianity defines itself. All one needs to do is go look for those definitions. There's no need to redefine what is already defined.