Alan Watts drew an interesting distinction between belief and faith. Referring to the root of belief in Middle English (lief, meaning "wish"), he said that belief is a heartfelt wish that things be or turn out a certain way; in other words, there is a way things should be and a way they shouldn't be, and belief is a wish that they be the way they "should." Faith, on the other hand, is trust in the truth -- things are the way they are, and that is what there is to work with. In other words, the only power I have is to play the particular hand that I'm dealt and trust that it will work out. In a specifically religious context there is a popular phrase: "The will of God will never take you where the Grace of God will not protect you." While of unknown origin, this phrase is consistent with numerous Biblical passages from both the Hebrew and Christian Canons and points to the essence of faith as trust.
But even if we accept Watts' definition of faith, we are left with some questions. First, faith in what? One might opt for a Panglossian faith that this is "the best of all possible worlds" and go blithely along trusting that everything is OK no matter how awful it seems, or one might abandon faith altogether for belief on the one hand, or, on the other hand, the view that the universe is random and nothing matters, or one might opt for the inflated ego of faith in oneself as the answer to it all, or blind faith, à la someone I knew who said that faith is "believing what you know cannot possibly be true."
My personal choice is faith in God -- not the anthropomorphic God of Western religion, but a panentheistic faith in a supreme power that is at the same time immanent (present) and transcendent, and that is the unity of all life expressed in an infinite variety of ways, moving toward its own realization in that unity being re-established.
I am including this expression of my own faith not because I think it's the right one or the best one but because I need an example for purposes of this essay and would not presume to use anyone else's faith as my example. Which brings me to my point: belief is a one-time event. You decide what you believe, and that divides the world into two camps -- call them good and bad, God and Satan, the way it should be and the way it shouldn't be, it doesn't matter. Even situational ethics or moral relativism does this -- black and white ethics or morals are bad, situational or relativistic ethics or morals are good. In this sense belief is easy -- in the words of a bumper sticker, "God said it, I believe it, that settles it."
With faith it's not so easy. First of all, faith has no proof -- if one is to have faith in "the word of God," the question arises, which word? The Bible, including the Hebrew and Christian Canons, the apocrypha, the discoveries in the Dead Sea Scrolls -- all of it is rife with contradictions. Belief-based religion is notorious for picking and choosing among the "word of God" to support particular views of what is right and wrong. Faith is, above all, trust -- trust that there is a truth that is only dimly reflected in human beings' attempts to represent it, and that will reveal itself when one is open to its unfolding.
And that trust is not a one-time event; it's a discipline. By wiring and by learning, we are predisposed to the question "is this good for me or bad" about everything in the world, and the "me" in that question quickly becomes "us" -- our family, tribe, nation, etc. In other words, we default to belief, and faith takes work to recover from our immediate reaction and return to the created position of trust and openness to how things will unfold. Also, in my own faith in God, I have to continually remind myself that while God's will operates immanently, God's perspective is transcendent and outside of time, so what appears to be an utter disaster now may in the long view be an important contribution toward the realization of that unity that is God.
So for me the question becomes how quickly can I recover from the latest threat or trauma and resume my discipline of faith, accepting what God/life offers me and discovering its significance (or lack thereof) in the fullness of time, while at the same time trusting that the commitments I have taken on -- to my family, to the world -- are also worthy of trust and that events that appear to be setbacks to those commitments will ultimately forward them, and it is the practice of that recovery that is the discipline of faith and the speed of recovery that is the metric for how much I am growing in faith.