1 Nephi 17

As Nephi again warns his brethren recounting all the miracles that they were aware with the house of Israel, he tells them -

"...that they should murmur no more against their father; neither should they withhold their labor from me, for God had commanded me that I should build a ship.
50 And I said unto them: If God had commanded me to do all things I could do them. If he should command me that I should say unto this water, be thou earth, it should be earth; and if I should say it, it would be done.
51 And now, if the Lord has such great power, and has wrought so many miracles among the children of men, how is it that he cannot instruct me, that I should build a ship?"  (Book of Mormon | 1 Nephi 17:49 - 51)

With all these miracles and even that the Lord could command the ocean to be dry earth, the idea of instructing Nephi to build a ship seems quite insignificant.