Faith and Diligence - 1 Nephi 16:28

And it came to pass that I, Nephi, beheld the pointers which were in the ball, that they did work according to the faith and diligence and heed which we did give unto them.

 Here, Nephi is telling us about the liahona and the principles by which it worked. There were devices in the past (and present?) which worked upon similar principles such as the urim and thumim. The important part here is the principles by which they worked. It says "faith and diligence and heed".

Heed means to put into action. This is important to faith. One may believe something with all of their heart and yet not put it into action, in which case they have proven their lack of faith. I may well believe that if I quit smoking for example, that my health will improve, and yet not act on that belief - this is equivalent to lack of wisdom and faith. I may well believe that God will reward me for being generous to the needy and yet never give of my time and resources. Again, a lack of faith.

Diligence is related to heed in that it requires action. But it implies a certain level of constant effort and consistency. To be diligent is to keep trying even when things aren't clear or when they are tough and rocky. This is a very important element to faith because there is not a person who seeks to have faith that is not tried. We may fail our trials from time to time, but if we are diligent, we will not give up in the face of failure. We will seek forgiveness and determine not to fail when next tried.