Charles Ellicott Commentary Numbers 26:53-56

"Unto these the land shall be divided for an inheritance according to the number of names. To the more thou shalt give the more inheritance, and to the fewer thou shalt give the less inheritance: to every one according to those that were numbered of him shall his inheritance be given. Notwithstanding, the land shall be divided by lot: according to the names of the tribes of their fathers they shall inherit. According to the lot shall their inheritance be divided between the more and the fewer." — Numbers 26:53-56 (ASV)

Unto these the land shall be divided ... — The general apportionment of the land, regarding the relative position of each tribe, was to be decided by lot, which was commonly regarded as the determination of God Himself, and in this instance, it undoubtedly was so. The extent of territory was to be determined by the number of names—i.e., of persons—in each tribe, and each inheritance was to bear the name of the ancestor of the tribe. Rashi says that the names of the twelve tribes were written on twelve scrolls of parchment, and twelve borders, or limits of land, on twelve others, and that they were mixed together in an urn.