Nephi had been feeling the weight of his divine responsibility and the dire consequences of his people’s failure to see the destruction that plainly lay before them. It was a moment of righteous and prophetic despair. Just at that moment, Yahweh pronounced a blessing and an endowment of great power that will last “forever.” Yahweh “will make [Nephi] mighty in word and in deed, in faith and in works.” Most importantly, God grants to him unconditional power (“all things shall be done… according to thy word”) for Nephi’s own righteousness confirms that “thou shalt not ask that which is contrary to my will.”
This promise somewhat parallels one granted to Joseph Smith:
Whatsoever ye ask the Father in my it shall be given unto you, that is expedient for you;
And if ye ask anything that is not expedient for you, it shall turn unto your condemnation. (D&C 88:64–65; see also D&C 11:14)
The promise has two parts. One is that the prophet is given power to ask and receive the desired result. However, this promise is accompanied by agency and responsibility. When Yahweh gives this gift to Nephi he emphasizes that it comes as a result of Yahweh’s trust. Surely God also trusted Joseph, but that later promise spells out the responsibility of being granted such power. The possibility of using it unwisely is an inextricable aspect of agency, to be accompanied by dire consequences.