Joshua 22:11-12

11And 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 over against the land of Canaan, in the borders of Jordan, at the passage of the children of Israel. 12And when the children of Israel heard of it, the whole congregation of the children of Israel gathered themselves together at Shiloh, to go up to war against them.