Alma begins discussing the continuum of faith at its very beginning, at the line separating “faith” from “not faith.” Now he describes the lowest form or smallest amount of faith it is possible to have. That lowest form is the simple desire to believe. This is why he calls it a “particle of faith.” It is just the smallest bit of faith.
What is essential, however, is that this desire, this “particle of faith,” be attached to action. Alma tells these people that they must exercise that particle of faith, “even if ye can no more than desire to believe, let this desire work in you, even until ye believe in a manner that ye can give place for a portion of my words.” The desire to believe edges over the line into faith when action occurs, even if it is a small action. The smallest action is to “give place,” or to accept the possibility of believing some of what is said. If the hearer immediately dismisses everything the missionary says, then faith cannot begin. Faith can begin only when the listener accepts the possibility that what the speaker has said might be true.
The best example of this particle of belief is found in Alma 22:18, when Lamoni’s father prays: “O God, Aaron hath told me that there is a God; and if there is a God, and if thou are God, wilt thou make thyself known unto me, and I will give away all my sins to know thee, and that I may be raised from the dead, and saved at the last day.”
How much faith did the king have? Not much. He readily admits that he does not know of Yahweh’s existence; but because Aaron has said there is a God, the king prays “if” there is a God, and “if” the being he addresses is God, and “if” he is also Aaron’s God, then—he promises action.
The result of this sincere prayer is that the king is overcome with the Spirit, carried away in Yahweh’s glory. The crux of the prayer is not his string of equivocations; they simply and honestly acknowledge that he is on a low level of faith. What made the prayer effective was his firm commitment to give away all his sins to know God. That part of his prayer actually gave place to a portion of Aaron’s words (to use Alma’s phrase), thus allow this very low form of faith to bring about a miraculous outpouring of the Spirit.
Reference: How universal are Alma’s stages of faith? Surely unusual people, such as prophets, need not go through all these steps? However, if we read Joseph Smith’s story in conjunction with Alma’s discourse, all of the essential steps of faith occurred. He definitely began with the lowest form of faith: a desire put into action.
At length I came to the conclusion that I must either remain in darkness and confusion, or else I must do as James directs, that is, ask of God. I at length came to the determination to “ask of God,” concluding that if he gave wisdom to them that lacked wisdom, and would give liberally, and not upbraid, I might venture.
So, in accordance with this, my determination to ask of God, I retired to the woods to make the attempt. It was on the morning of a beautiful, clear day, early in the spring of eighteen hundred and twenty. It was the first time in my life that I had made such an attempt, for amidst all my anxieties I had never as yet made the attempt to pray vocally. (JS—H 1:13–14)
Joseph’s desire leads him to the scriptures, where he found information that he acted upon by attempting a vocal prayer, a new experience for him.