What is it that you are believing? Faith "is the assurance of things hoped for, the conviction of things not seen" (Hebrews 11:1 ESV). C.S. Lewis defines faith as "the art of holding onto things your reason has once accepted, in spite of your changing moods" (Mere Christianity). If you really believe the things that Jesus claims about himself, and I mean really believe... your life has to reflect that.
Let's look at an example. We are all convinced of the force of gravity. We know that if there is nothing beneath us, we will fall. We believe in the force of gravity, and it affects the way that we live. Because we are assured and convicted that we will fall toward the surface of the earth, we do not walk off the edge of Niagara Falls in order to get a closer look. Our faith that gravity will continue to do what it has shown itself to do in the past affects the way we live. It cannot have no effect. If we believed in gravity the way that many claim to believe in Christ, then there would be nothing stopping us from walking out into nothingness and plunging into the churning waters of the Niagara below. This is what James, the brother of Jesus, is talking about when he says, "So also faith by itself, if it does not have works, is dead" (James 2:17).
I have been guilty of claiming a faith that does not translate into each step I take. I ask God to make my faith true and to have it affect the way I eat, talk, and walk. I challenge you to do the same.