Again, Jesus turns specifically to the twelve disciples. While Jesus had taught that those who followed him were a light to the world (3 Nephi 12:14), the disciples are expressly given the command to be that example. They are to be the teachers of the people, and the guardians of the covenant made with the house of Joseph of old.
When Jesus tells the disciples that “this is the land of your inheritance,” he is not specifically giving land to the twelve, but defining their realm of operation. The New World has been given to the house of Lehi, and the twelve represent the New World and will have responsibility for it. This is not a promise of land ownership, but of responsibility to the people on the land. Even those not in Bountiful at this time must receive the light of the gospel, and that is in the hands of the twelve to direct.