Many understand faith to be equivalent to belief. Part of this may be a question of translation, the same Greek word translated as faith—πιστις pistis—can also be translated as belief. The word belief has a number of different connotations, most of which have to do with knowledge and are understood in that light.
In matters of religion, people will frequently be asked questions like “Do you believe in God?” or “Do you believe in Jesus?” but the question is somewhat ambiguous: does belief here mean “convinced of the existence of” or “give credence to the claims of”? That particular ambiguity was exploited by Mark Twain when he was once asked, “Do you believe in infant baptism?” Twain famously, and brilliantly, replied, “Believe it? Hell! I’ve actually seen it done!”
The question “Do you believe in God?” sometimes comes across like “Do you believe in Santa Claus?”—it is a question ascertaining whether you believe in the existence of God. But “Do you believe in Jesus Christ?” is a little different.
With rare exception, most people accept that Jesus of Nazareth was a historical personage, who actually lived and died. In this case, it appears that the question is designed to ascertain whether you believe that he was who the Church, or perhaps even this individual questioner, says he was. That is, belief in this context points to more than affirmation of something’s existence, like believing in Santa Claus, Sasquatch, or UFOs; this is about assent to doctrine. It’s not so much do you believe that Jesus exists, but do you believe he exists in the right way?
Much of the warrant for this kind of thinking in the English speaking world comes from verses like:
John 2:11 Jesus did this, the first of his signs, in Cana of Galilee, and revealed his glory; and his disciples believed in him.
Gal. 3:22 But the scripture has imprisoned all things under the power of sin, so that what was promised through faith in Jesus Christ might be given to those who believe. (NRSV)
Here “believed in him” makes no sense if we’re talking about the existential sense of the word. “Do you believe in Jesus, Peter?” “Believe in him? Hell! I’ve seen him!” Here, the sense in verses like John 2:11 (and many others in that Gospel), and the verse from Paul, seem to suggest the importance of believing about Jesus in some way. Salvation is given to those who believe in Jesus, that is, believe in certain things about him.
As I noted above, the word that is often translated as belief in English is the Greek word pistis, which can also be translated as faith. And so the verse from John’s gospel could just as correctly be translated: “…and his disciples had faith in him.” A translation that might make a little more sense in context. The verse from Paul’s letter to the Galatians is interesting because the word pistis or its related verbs occurs twice in the text: “…what was promised through pistis in Jesus Christ might be given to those who pisteusosin.” So, this verse could be translated a number of ways, including: “…given to those who have faith.”
Faith has so frequently been associated with understandings of belief that we sometimes forget that faith means trust. To have faith in someone is to trust that person. Someone who has committed infidelity (from the Latin fides “faith”), has not been loyal and cannot be trusted. So, it is just as likely that all the verses in scripture speaking of belief are really speaking about trust.
But there’s another interesting clue in the Greek text. The phrase translated “through faith in Jesus Christ” found in the writings of Paul in this letter and elsewhere is δια πιστεως Ιησου Χριστου dia tou pisteōs Iēsou Christou, which literally means “through the faith of Jesus Christ”—not in, of. This leads to some intriguing possibilities: that it is neither intellectual assent to some understanding of Jesus, or even just having faith in Jesus, but relying on Jesus’ faith. There are some who argue that Jesus’ faith is so strong that it saves even you. There are others who see this as a model: the kind of faith that Jesus had is the kind of faith you’re supposed to have, trusting in God even up to the alienation of the cross. That is the faith that saves: the faith of Jesus Christ.
So, why are people more likely to equate faith with belief rather than with either trust or these other ways of understanding faith?
Because if you’re craving certainty and predictability, trust is hard and assent to doctrine is easy. If you tell me that all my uncertainties will go away if I merely accept certain propositions to be true, then I’m more likely to sign up for that bargain. Telling me to just have faith and trust in God doesn’t necessarily remove any uncertainty.