The first phrase of verse 1 repeats the concept of Lehi’s prophesying after receiving the plates. The inserted information that we have as 1 Nephi Chapter 6 has ended, and we are now returning to Nephi’s intended story.
The next major event has the sons returning to Jerusalem again. The first time was to provide for the spiritual welfare of the future Nephite nation. It would have provided that for the Lamanites as well, had they so desired. This return is to provide for the progeny that would create that nation. The first time was hazardous; this trip was much less so. It is probable that there was some joy and anticipation for this task, as opposed to the trepidation of the journey for the plates of brass.
In verse 2, Nephi mentions that they were to go to the land of Jerusalem. In any ancient city, there were the city proper and the outlying lands that looked to the city for commerce and protection. The command might have indicated that Ishmael lived in the outskirts of Jerusalem, although verse 3 only mentions Jerusalem. It is possible that verse 3 is using the city as the reference to the whole of the land of Jerusalem.
We don’t know why it was Ishmael who was chosen. Erastus Snow recorded that Joseph Smith said that the lost 116 pages included the information that Lehi was from the tribe of Manasseh, and that Ishmael was from the tribe of Ephraim. Ariel Bybee suggests that it is possible that there was some kinship connection through Sariah. The Israelite tradition of cross-cousin marriages would at least suggest that possibility.