Thematic Bible: The eastern half assists in the conquest of the country west of the jordan river

The children of Reuben, Gad, and the half-tribe of Manasseh crossed [over] armed before the {Israelites}, as Moses told them. About forty thousand armed for fighting crossed [over] before the presence of Yahweh to the plains of Jericho for battle.

"And I charged you [all] at that time [when I] said, "Yahweh has given you--to [all of] you--this land to possess. All the {warriors} shall cross over, ready to fight, before your brothers, the {Israelites}. Only your wives and your little children and your livestock (I know that {you have much livestock}) must stay in your towns that I have given you, until Yahweh shall give rest to your brothers as [he did] to you, and also they take possession [of] the land that Yahweh your God [is] giving to them beyond the Jordan; then they may return, each [one] to his possession that I have given to them.

To the Reubenites, the Gadites, and the half-tribe of Manasseh Joshua said, "Remember the word that Moses Yahweh's servant commanded you, saying, 'Yahweh your God [is] giving rest to you, and he is giving you this land.' Your wives, your little children, and your livestock, they will remain in the land that Moses gave to you beyond the Jordan. {All of the best fighting men} will cross armed in front of your families; they will help you read more.
until Yahweh gives rest to your families as well as to you. They will take possession of the land that Yahweh your God [is] giving to them. Then you will return to your own land and take possession of it, [the land] that Moses the servant of Yahweh gave you beyond the Jordan {to the east}."