Nephi advised future readers that his overall purpose in writing the words of Isaiah into the record is to persuade people, the whole house of Israel (plus all who would be adopted into the house of Israel), to remember the Lord, their Redeemer.
Once again Nephi called attention to the physical weakness he felt when full of the workings of the Spirit (see also 1 Nephi 1:5–20; 17:47). Nephi’s comment about the workings of the Spirit leaving him weary was not a complaint but rather an expression of gratitude that the Lord had watched over him so carefully. Intense experiences with the Spirit and power of God do leave mortals feeling weakened. Even the mortal Jesus experienced this when a woman touched the hem of his garment and was healed. Mark recorded that Jesus felt strength go out of him (Mark 5:27–30).
Ancient prophets foresaw the future Jews at Jerusalem at around 600 b.c., and they foresaw groups broken off from the olive tree of Israel, such as the Lehite colony (“ye who are a remnant of the house of Israel, a branch who have been broken off”; 1 Nephi 19:24). The testimonies of these prophets of old were engraved on the plates of brass.