Faith is a loaded word. It's more than just your religious beliefs.
I have faith that when my mother told me 2+4=6 that she was right.
I have faith that the grass grows green and the clear summer sky will be blue because my father told me that.
I have faith that when I sit into my chair, it won't break because it's been there to hold me up time and time again, without creaking, cracking, or bending. My chair has historically been there to hold me up.
I have faith that when my death comes, my family will be sad and hold a service for me. I've death and the grieving process hundreds of times. Even when the families are happy that the deceased no longer suffers from their illnesses and pains, the family still misses them.
Faith seems like it's a matter of believing because you have information that leads you to want to follow and listen to the potential for truth.
So how does faith fit into religion?
We all see how intricate, how detailed, how amazingly our world all fits together. We've had situations that lead us towards the truth - that there is someone, something greater out there.
Then we have this book - THE Book. It tells about this Someone and how everything came to be. And while it's a little confusing at first... and a bit much to take in... we see that there's no reason to doubt it. The Something tells people to go here, do this, eat that.... and when they listen, they are successful. When the people don't, they fail.
Some time later, a Someone comes along and says that he has the power of the Something. Then he proves it. He works miracles (feeds the masses, heals the sick, raises the dead).
We have reason to believe what he says. And even the people that don't want to admit that they're wrong and this Someone is right.... document all the stuff that Someone can do.
So then a few years later, we have a bigger book, outlining what the Something said, backed up by the works of the Someone.
So we read and try to understand the truth contained in the book of the Something and Someone.
And we try to find a way to see the Something everywhere we go, because he said he was here with us, always.
And so even though we can't always hear, can't always see, can't always feel Something, we know it's here with us anyway. So we draw reference and implication from Someone's book, and try to figure out what we should do next. That's where the faith really starts to take effect.
Even though I have no tangible, undeniable proof against it, I have enough reasons to follow directions from Someone.
And if I find out that 2+4=7, I'll be really messed up. If I find out the grass is orange and the sky is red, I'll be disappointed. If my chair breaks, I'll have a sore butt. If my family doesn't grieve my death, I won't know any different. If my faith in God is misplaced, I'm out nothing but a little time, money, and energy. Which I would have spent on other things that make me feel good... so there's really no loss there - I am contented when I help others.
Just so it's not a point of confusion - I don't have faith "just in case." I'm not one of those that says "I'll believe in God because I'm scared of the alternative." I fully and completely believe in God and Jesus because of my experiences. I'm just saying that if I'm wrong, I've lost nothing.