There is a difference between faith, belief, and trust.
The following illustration should help make this clear.
- Faith is believing the truth. For faith to be faith, we must have a reason to believe.
- Belief is an element of faith but not the whole.
- Trust is nearly the inverse of faith, and God requires it as well as faith. It is believing in spite of the evidence.
When your parents were courting, they had to check out each other's intentions and collect "evidence" that he/she was the right person. Now they have been married for many years, and know if their expectations and due diligence were warranted. They might have "believed" in each other from the beginning, but their belief might have been misguided. It is when we have the substance of that for which we hope, the evidence of the unseen thing that is believed in playing out in actually before us, that distinguishes mere belief from faith.
Now suppose that after 20 years of marriage, someone comes to you and your mother and shows you proof that your dad is really a drug dealer and Russian spy. You are given irrefutable evidence (at least in the moment), shown pictures, receive testimony, etc. that your father is a disgustingly wicked and traitorous person. You can offer (in this moment, at least) no response or counter... as this is all new, and you are overwhelmed by "the facts". Yet you do not believe for a moment that it is true. You discount the present "evidence", because you and your mother know your father.
This... would be trust. It is believing in spite of what appears to be the case. It is a resistance to the "tyranny of the immediate" for what is known and believed when the weather was better and the mind was clearer.
As you can see, trust in this sense is nearly the opposite of faith, and clearly God requires it in the moment of temptation. When human limitations are assailed with a barrage of facts or desires, trust is required.
Both faith and trust are the same in that the ultimate object of both--if valid--is God. In the one case we are sure of what we believe, in the other we hold to it despite the barrage of "facts" that the world, the flesh, or the devil is presently assailing us with.
Faith is believing the truth. For it to be faith, it must be true, we must apprehend it, and we must embrace it. Minus any of these (if what we are embracing is false, if God has not spoken it to US--even it is true, or we simply agree with it and do not enter into the truth) then it might be something; but it is not faith.
If you have not seen it already, we have a full Bible Study on this at http://www.acts17-11.com/faith.html
Another illustration of the "substance" and "evidence" of faith would be running down a basketball court a good 15 feet ahead of anyone else--headed for the goal. You have not done the lay-up or slam-dunk yet, but you can taste it, feel it. It is going to happen, you just know it is. It has not happened yet, but in such moments the future (an example of an "unseen thing") is so prescient and palpable that it is almost like the moments leading up to it and the thing itself are of "one piece".
Perhaps you have had this experience, this surety of what is yet unseen... It is a distinct thing. It is not mere belief. It is not blind; there is ample and sound reason for it. It is not in opposition to what the evidence suggests. Faith is the palpability of things looked forward to, the sureness of what remains to play out.