HERE’S A QUICK question to answer. Don’t overthink it; just say the first thing that comes to your mind. Ready? Here goes: what does the word “Christ” mean to you?

For many of us, I suspect, the knee-jerk response would be, “That’s Jesus. Duh.” Indeed, we can be so used to saying the name “Jesus” together with “Christ” that we don’t stop to think of them differently, and may even use them interchangeably. We’ve been taught that “Christ” isn’t Jesus’ last name (though you might not know that from the way some people swear). But what else does it mean?

I think here of Peter’s famous confession of faith in Mark 8. Jesus was walking with the Twelve in the vicinity of Caesarea Philippi, and he asked them what the general gossip was about him. Who did other people think he might be? “Some say you’re the John the Baptist, back from the dead,” they reported. “At least that’s what Herod seems to think, and it’s got him spooked. But others say Elijah, or maybe one of the other old-time prophets.”

“Okay,” Jesus replied. “But what about you? What do you think? Who do you say I am?”

I imagine the disciples looking at each other, not wanting to answer incorrectly, silently negotiating who would speak, if anyone. Not surprisingly, Peter is the one who spoke up. If anyone other than Peter responded, the Bible doesn’t say. But Peter’s response is the important one. “You are the Messiah,” he said simply (Mark 8:29).

That’s the New International Version’s translation, and I agree with it. But it’s worth noting that the Greek word Mark uses here is Christos, from which we get “Christ.” In both the Hebrew and Greek, both titles, “Messiah” and “Christ,” refer to someone who has been anointed with oil.

When Peter declared Jesus to be the Christ, he was speaking from within the culture and tradition he knew, believing that God would one day send his Messiah, an anointed king born of the line of David, to rescue his people from their oppressors. Peter and the other disciples no doubt expected Jesus to use his miraculous power to somehow defeat the Romans and get them out of Palestine so he could set up his own earthly kingdom and bring back the glory days. Thus, understandably, the NIV translates Christos as “Messiah” instead of “Christ” in Mark 8.

But a lot happened between that time and the time John wrote his letters. With the unexpected death and resurrection of Jesus, and his ascension back to the Father, the disciples’ understanding of Jesus was forced to grow and adapt. Decades later, John would write this:

Everyone who believes that Jesus is the Christ is born of God, and everyone who loves the father loves his child as well. (1 John 5:1, NIV)

“Jesus is the Christ,” John says. Well, of course, we might think, he’s Jesus Christ. But if instead of Peter, John had been the one to answer Jesus’ question that day near Caesarea Philippi, what would he have said? I imagine his answer would have been the same or similar. Peter may have been the one to speak, but surely the disciples had discussed with each other the matter of Jesus’ identity.

What John would not have said — indeed, what he would not have been able to say at that point in time — is most of what he writes about Jesus in the opening chapter of his gospel. John would not have said to Jesus, “You’re the one through whom all things were created.” He would not have said, “You’re the eternal Word made flesh.” It took time, experience, and much prayerful reflection for him to come to that understanding of Jesus. Thus, when he writes many years later that “Jesus is the Christ,” he no longer means merely the Davidic Messiah as an earthly king.

Think back on all the things John writes in his letter to correct the false teaching about Jesus that had split the community, everything he says to reinforce a right understanding of Jesus’ identity. He begins 1 John in the same place he begins his gospel, with eyewitness testimony that Jesus is the Word. He opens chapter 2 by describing Jesus as our heavenly Advocate when we sin, indeed, the atoning sacrifice for the sins of the world. In chapter 3, he names Jesus as the one who has destroyed the work of the devil. In chapter 4, he declares the foundational importance of believing that Jesus Christ came in the flesh.

And throughout the letter, he labels those who do not believe these things antichrists. “Who is the liar?” he asks rhetorically in 2:22. “It is whoever denies that Jesus is the Christ. Such a person is the antichrist—denying the Father and the Son.” To be anti-Christ is not to be anti-Jesus. It’s not to deny that Jesus existed, but to deny that Jesus is the Christ, with everything that the title “Christ” had come to mean to John.

IN A SENSE, Jesus’ question to Peter and the disciples — “Who do you say that I am?” — is the one that would later divide John’s community. Some members of the community had developed ideas about Jesus that mixed in worldly values and philosophies. To some extent, that’s unavoidable; we’re intrinsically social creatures who grow up learning from others around us how to look at and speak of reality. But in John’s community, some had taken this to the point of heresy, to the point where they pushed the eyewitness, apostolic gospel to the margins and insisted that others do the same. Mixing in the world’s ideas, in other words, mixed up the gospel, and disastrously so.

So, who do you say Jesus is? The question mattered then, and it still matters now.