Charles Ellicott Commentary Joshua 22:11

"And the children of Israel heard say, Behold, the children of Reuben and the children of Gad and the half-tribe of Manasseh have built an altar in the forefront of the land of Canaan, in the region about the Jordan, on the side that pertaineth to the children of Israel." — Joshua 22:11 (ASV)

Have built an altar. —Rather, have built the altar. As is evident from Joshua 22:28, it was a representation of the altar of Jehovah: a copy of the one altar which He had given to Israel for sacrifice. The design was to set up on the east of Jordan a likeness of that altar which was established on the west, that the tribes on the other side of Jordan might appeal to it as a proof that they also were the people of Jehovah.