With the Midianites out of the way, what lay before the nation of Israel was a piece of prime real estate that, in the eyes of the Israelites, seemed perfect for pasture-grazing.
Reuben and Gad spot it first—or at least are the first to do anything about it—and approach Moses with a proposition: Let the tribes of Reuben and Gad claim their promised land inheritance on the other side of the Jordan River.
This request is kind of a mixed bag. On the one hand, it makes perfect sense. The Midianites were a fortress of a people, and now they have been mostly wiped off the face of the earth (though they’ll reappear later in Scripture). Their land is fertile, luscious, and vast. Why let it go to waste?
On the other hand, staying put signals a discouragement to the rest of the nation. If they’re going to war, their brothers should go with them, Moses argues. Failure to do so will breed discouragement through the ranks.
But there’s a few other reasons Reuben and Gad’s request is a little hairy. When you fast forward to Joshua 13, the land distribution is decided via lot and population. Every tribe has their own allotment that’s perfect for them and decided upon by God. For Reuben and Gad to claim their own reeks of greed and selfishness.
The other reasons have to do with geography and topography. Then, as is now, boundary lines for towns, counties, nations, and districts, etc, are defined by natural borders.
The crest of the Appalachian mountain range, for example, separates Tennessee from North Carolina. Here in Texas, the Rio Grande River is our southern border, and the Red River separates us from the dreaded Oklahomans.
The Jordan River is a natural dividing line between east and west; anything to the east is portrayed in Scripture as an “other.” Joshua 3-4 creates a dramatic picture of this, when Joshua crosses the river and makes a memorial to signal the beginning of the conquest of Canaan.
To intentionally put yourselves on the other side of a natural border is to court division. But it also places them in direct conflict with any enemy that may attack from the east and hinder aid from the rest of the tribes.
History bears this out. The Syrians, the Assyrians, and other nations naturally hit these tribes first before entering the main Canaan territory. 1 Chronicles 5:26 explicitly states that the Transjordan Tribes were the first ones taken into exile.
So why did they ask for the land? Simple: Because it looked awesome. In their mind, this area offered them everything they needed to create the best life for their families.
Unfortunately, just like Lot with Sodom and Gomorrah, they also realized too late the price of setting up your home in an area so fraught with danger.