Notes on the Bible, by Albert Barnes, [1834], at sacred-texts.com
By lot - We are not told in what manner the lot was cast. Perhaps two urns were employed, one containing a description of the several districts to be allotted, the other the names of the tribes; and the portion of each tribe would then be determined by a simultaneous drawing from the two urns. Or a drawing might be made by some appointed person, or by a delegate of each tribe from one urn containing the description of the ten inheritances. The lot only determined in a general way the position in the country of the particular tribe concerned, whether north or south, etc.; the dimensions of each territory being left to be adjusted subsequently, according to the numbers and wants of the tribe to be provided for. Since the predilections and habits of two tribes and a half were consulted in the apportionment to them of the trans-Jordanic territory Num 32:1 there is no objection to the supposition that something of the same kind may have taken place, subject to the divine approval, in the distribution of the lands to the nine and a half other tribes; and the lot would thus be appealed to as finally deciding the matter and foreclosing jealousies and disputes.
It is apparent that the casting of the ten lots did not take place simultaneously. The tribe of Judah had precedence, whether by express appointment or because its lot "came up" first, does not appear. It was, as it seems, only after this tribe had settled upon its domains, that further lots were drawn for Ephraim and the half tribe of Manasseh. After this a pause, perhaps of some duration, appears to have occurred; the camp was moved from Gilgal to Shiloh; and the further casting of lots for the other seven tribes was proceeded with at the instigation of Joshua (see Jos 18:10).
The children of Judah - No doubt, in particular, the kinsmen of Caleb, and perhaps other leading men of the tribe. These came before Joshua, with Caleb, in order to make it manifest that they supported his claim, to be secured in the possessions promised him by Moses before the general allotment should be made to the tribes (compare the marginal references).
Moses sware - i. e. God swore; and His promise, confirmed by an oath, was communicated, of course, through Moses.
Forty and five years - The word of God to Moses was spoken after the return of the spies in the autumn of the second year after the Exodus Num 13:25; subsequently, 38 years elapsed before the people reached the Jordan Num 20:1; after the passage of the Jordan seven more years had passed, when Caleb claimed Hebron, before the partition of the land among the nine tribes and a half. These seven years then correspond to the "long time" Jos 11:18 during which Joshua was making war with the Canaanites. They are in the sequel of this verse added by Caleb to the years of wandering, since during them the people had no settled abodes.
The Anakims had in the course of Joshua's campaigns in the south been expelled from "this mountain," i. e. the mountain country round Hebron, but they had only withdrawn to the neighboring cities of Philistia Jos 11:22. Thence, they had, as must be inferred from the text here, returned and reoccupied Hebron, probably when Joshua and the main force of the Israelites had marched northward to deal with Jabin and his confederates. Caleb finally drove out this formidable race and occupied Hebron and its dependent towns and district permanently. See Jos 15:13 following.
A great man - literally, the great man; i. e. the renowned ancestor of the tribe, regarded as the founder of its greatness Jos 15:13.