Joshua here is reminding the two and a half tribes that Moses had yielded to their request and had promised to them land on the east side of the Jordan River, while the rest of Israel was to go across the Jordan and occupy the territory on the west side.

The tribes of Reuben and Gad were wealthy in cattle, and there were plains on the east side of the Jordan River that were well suited to raising animals. Therefore Reuben, Gad, and half the tribe of Manasseh desired to remain on the east side of Jordan and receive their inheritance there.

Now the children of Reuben and the children of Gad had a very great multitude of cattle: and when they saw the land of Jazer, and the land of Gilead, that, behold, the place was a place for cattle; (Numbers 32:1)

Moses, after expressing the greatest displeasure over their request, agreed to give them the lands east of the Jordan that had been ruled by Sihon and Og—two kings that the Israelites had defeated in battle. But the men of these two and a half cattle-loving tribes were required to cross over the Jordan River and fight alongside the rest of the tribes until the land of Canaan (on the west side of the Jordan) had been subdued.

Speaking to Reuben, Gad, and half of the tribe of Manasseh, Joshua commanded:

Your wives, your little ones, and your cattle, shall remain in the land which Moses gave you on this side Jordan; but ye shall pass before your brethren armed, all the mighty men of valour, and help them; (Joshua 1:14)

Even though they had received their inheritance on the east side of the Jordan River they were required to cross over the Jordan and help the rest of the tribes enter their respective inheritances.

The problem with remaining on the east side of Jordan was that Reuben, Gad, and the half of the tribe of Manasseh were separated by the Jordan River from Jerusalem, from Zion, from the Tabernacle of the Congregation, from the Altar of Burnt Offering, from the priesthood, from the Ark of the Covenant, and from the manifestation of the Glory of God Himself.

The request of the two and a half tribes was denounced vigorously by Moses who perceived immediately the error of their hearts.

Reuben, Gad, and half the tribe of Manasseh cared more for their cattle than they did for God. It was of little interest to Reuben, Gad, and the half of Manasseh whether or not they were close to the Presence of God, who manifestly was in the midst of Israel and who was moving forward with the Ark of the Covenant; whether or not they would be present to see the fulfillment of God's promises to Israel; whether or not the other tribes would be successful in obtaining their own inheritances.

Their hearts were with their cattle.

To be continued.