Nephi's demonstration of power most literally shocked Laman and Lemuel into a period of humility and obedience. They relent from their intent to sabotage the building of the ship, and instead participate in the project.
It is interesting that while Nephi had been shown by the Lord the way to build the ship, he yet returned to the Lord from time to time for more information. A single communication from the Lord showing us direction is not necessarily the only direction that we need. As did Nephi, we should return to the source for more information.