“So the Reubenites and the Gadites and the half-tribe of Manasseh returned home. They parted from the Israelites at Shiloh, which is in the land of Canaan, to go to the land of Gilead, their own land that they had taken possession by command of Yahweh through Moses. When they came to the region near the Jordan that lies in the land of Canaan, the Reubenites, the Gadites, and the half-tribe of Manasseh built there an altar by the Jordan, an altar of a great size. The Israelites heard that the Reubenites, the Gadites, and the half-tribe of Manasseh had built an altar at the frontier of the land of Canaan, in the region near the Jordan, on the side that belongs to the Israelites. When the Israelites heard of it, the whole assembly of the Israelites gathered at Shiloh, to make war against them.”
This is an odd incident since it talks about a separate altar built on the west side of the Jordan by the east side tribes. This starts a war between the East and the West Jordan tribes. Notice the change in tone. The west bank tribes are referred to as ‘the Israelites,’ while the eastern tribes retain their tribal names. The west bank tribes believe that they are the true Israelites while the east bank tribes are not.