As Nephi discourses on the calamities of the last days, he sees the need to add in a comfort for the righteous. Nephi assures his brothers that the Lord "will preserve the righteous by his power" even amidst the "fulness of his wrath." At the end of the verse he explicitly cites a prophet, but does not indicate which prophet. While it might be assumed to be Isaiah as he has been explaining Isaiah, I cannot find the precise antecedent for the specific promise that the righteous "shall be saved, even if it so be as by fire." The meaning of this last verse is not that the fire will save the righteous, but that the righteous will be preserved, even if the "fullness of his wrath" were to be fire and burnings as have been predicted.