West of the Jordan is introduced by Good News Translation in order to clarify for the reader the location of this territory in the land of Canaan.

Eleazar the priest was the son and successor of Aaron (see Deut 10.6); together with Joshua and the leaders of the families of the Israelite tribes, he assigned the territories to the nine and one-half western tribes. (See Num 34.16-29, which names Eleazar and Joshua, and a representative from each tribe.)

The passive was divided may necessitate considerable restructuring in order to indicate who divided the land among the people of Israel. In identifying the persons who did the distributing, it really seems unnecessary to qualify Joshua as son of Nun, since he is the only Joshua with whom the readers are familiar. On the other hand, to specify Eleazar as the priest is helpful, since most readers are not as familiar with him. The entire first verse may be translated, “Eleazar the priest, Joshua, and the leaders of the families of the Israelite tribes divided the land of Canaan west of the Jordan River among the people of Israel. And this is how it was done.”

Quoted with permission from Bratcher, Robert G. and Newman, Barclay M. A Handbook on Joshua. (UBS Helps for Translators). New York: UBS, 1983. For this and other handbooks for translators see here .