What does Jesus mean when he says in John 10:30 that "I and the Father are one?" Are the words self-explanatory, or do we need the theological language of creeds and confessions to understand precisely what he means? And does it matter if we are not precisely clear on his meaning? In this very important article, Richard Barcellos explains what Jesus means, why it matters so very much and how valuable the language of our creeds and confessions can be.