According to Brant Gardner, the return to the land of Jerusalem was likely to have shaken what little faith that Laman and Lemuel possessed, since Jerusalem had obviously not been destroyed. With this in mind it is fascinating that the argument that Nephi puts forth here in continuing to seek to obtain the plates of Laban is a defense of his father's prophecy that Jerusalem would be destroyed, and if they stayed there after they had been commanded to leave they also would perish (see 1 Nephi 3:18). Nephi reminds his brothers that the entire journey of their family is a command from the Lord, and that they should obtain the records in order to preserve unto their children the language of their fathers (see v. 19). Nephi's reasons for obtaining the plates have validity only when we understand that Nephi knew that their descendants were to be cut off from their previous culture. Perhaps Laman and Lemuel were thinking that they would "lay low" for a while and then return to their own people. Nephi's argument that the plates were essential to their cultural preservation (see v. 20) indicates his understanding that this journey was one which would completely and inalterably sever physical ties with their land and culture (he had been told that they would be led to "a land of promise"--see 1 Nephi 2:20). Thus the need to preserve the scriptural heritage. [Brant Gardner, "Brant Gardner's Page, "[http://www.highfiber.com/] ~nahualli/LDStopics/1 Nephi/1 Nephi3.htm, pp. 10-11]