1 Nephi 17:16-22 Up until here, Nephi's preparations to build a boat had been purely intangible,though necessary. They consisted of communications with the Lord -- spiritual preparation. However, when Nephi starts to make tools for the construction of the ship, his brothers take note. Their disbelief is that they do not think that Nephi can construct a ship. Nephi says that they complained though because they didn't want to work. So there are two obstacles for Nephi to overcome. First, he needed to persuade them that he could build a boat. Second, he needed to solicit their help in doing it -- he needed his brothers' help. When Nephi mourns because of their disbelief, he is not mourning because he thought he could build a boat as his brothers so perceived it, but he is mourning because they do not believe. They lacked the perspective looking back and the vision to move forward. Their perceptions of their last eight years in the wilderness was miserable. Nephi's brothers...
A personal study of the Book of Mormon by Brent Leavitt,
a member of the Church of Jesus Christ of Latter-day Saints.