Someone has said that,
"Faith is believing a thing is so,
When it appears it is not so,
In order for it to be so,
Because it is so."
I think this sums up what faith is for the Christian person very well. Faith is active, not passive. By this I mean, faith is never inert; I can't say I believe something - really believe it - without it having a corresponding effect in my life in some way. This is what the apostle James was getting at in his letter in the New Testament. "Faith without works is dead," he declared (James 2:18-26). Real, genuine trust in something, having faith in it, always manifests eventually in action. For example, if I trust that the rope bridge will hold my weight as I cross it, I will step out onto it and walk its length - even if the bridge bobs and sways a lot as I do; if I trust that the chair I'm wanting to sit in will hold me, I will plunk myself down on it, even if I've never sat in it before; if I trust that my dentist can properly fix my aching tooth, I'll let him stick a needle into my gums repeatedly, then drill out my tooth, fill it, and charge me a ridiculous amount for doing so. The same is true for the faith I exercise in God and His truth. If I trust in Him and in what He has said is true, this will be reflected in how I live.
Knowledge, by itself, is not faith; knowledge is necessary to faith (as the Bible verses I posted to you earlier in this thread indicated), but faith is the result of knowledge. God's given to all of us the capacity for faith, for trust in, various things. We can't function as human beings without the exercise of faith, of trust, in other people (doctors, dentists, barbers, restaurant cooks, other drivers on the road, etc.). Atheists are just as much people of faith, then, as Christians are. Where they differ in this regard is in what they put their faith, their trust. The Christian has come to know the truth about God, Christ, the Gospel and themselves and trusting that all they know about these things is true, they act accordingly.
This is what Paul described in his letter to young Timothy:
2 Timothy 1:12
12 ...I know whom I have believed, and I am convinced that he is able to guard until that Day what has been entrusted to me.
Do you see the chain of things here? Paul knew, then believed and, convinced of the truth of what he knew, he then entrusted himself to God. To summarize: knowledge>belief>action.
Christian faith, then, is active. It arises from, and responds to, knowledge, to truth, by taking corresponding action. The person who says, "I believe!" but in whose living there is no evidence of their belief - particularly when it is obvious their belief should shape their living - is full of baloney.
So, what does the shape of your living reveal about what you really believe?