I believe reason is the vehicle that gets us to a point of making a good decision. Regardless of the decision, we need to use our God given brains to think before we act. Just because we think before we act does not mean we are not acting with faith. It simply means we are being careful to make sure we are not being deceived.
Here is the point I have been getting to. Confusing believing with faith causes us to trust our beliefs to save us. Unless we act on what we believe there is no faith involved.