Rashi: To teach us that the Goral actually spoke, ¹ thereby demonstrating that the lots worked via Ru'ach ha'Kodesh.

Ramban and Seforno: To teach us that also the families of each tribe received their portion of land via a Goral. ²

Bava Basra, 122a: To teach us that Eretz Yisrael was distributed by means of the Urim ve'Tumim. ³

R. Bachye #1: The Goral determined who received better-quality land and who received inferior-quality land, and the former had to pay the latter the difference. ¹

R. Bachye: #2: It prevented quarrels among the tribes as to who should receive what, ² and that no-one would covet the other one?s portion, but would acknowledge that it comes from Hashem. ³

Ramban: It implies that a larger tribe received a larger portion, and a smaller tribe, a smaller portion.

Sifri: It teaches us that the land was divided by assessment - a Beis Kur (of poor-quality land) against a Beis Sa'ah (of superior-quality land). ¹

Oznayim la'Torah (citing the Ha'amek Davar): In the event that two people of equal standing inherited two pieces of land which could be divided in two ways, the Goral decided how to divide it.

Bava Basra, 122a: It teaches us that each tribe received its portion according to the Goral, irrespective of whether it received a large portion - because it was small in number - or whether it received a small portion - because it was large in number - a proof that the Eretz Yisrael was divided according to the tribes and not according to the people. ²

Yerushalmi Yoma, 4:1: It teaches us that - besides the fact that Eretz Yisrael was divided via Goralos and the Urim ve'Tumim, it was also divided via money (taking into aount the vakue of the land) - inasmuch as someone who lived closer to Yerushalayim received a smaller portion of land than someone who lived far from Yerushalyim - 'One Beis Sa'ah in Yehudaah was equivalent to five Beis-Sa'ah in the Galil'. ³