The Lord has provided Nephi with a sort of compass (later identified as the Liahona) to guide him to the New World. But when the brothers bind Nephi, he can’t use the compass, and they are too unrighteous to make it work. No one knows exactly what the Liahona looked like, except that it was a round ball that was small enough to be handled easily by one person, and that it had two spindles that would point the direction to take.