Joshua 22:25

For the LORD hath made Jordan a border between us and you, ye children of Reuben and children of Gad; ye have no part in the LORD: so shall your children make our children cease from fearing the LORD.

For the Lord hath made Jordan a border between us and you, ... The country west of Jordan was, strictly speaking, he promised inheritance, the holy land. And, according, a remarkable difference was created in the feelings, as well as the language, of the Hebrews in regard to the country which lay east, and that which was situated on the west of the Jordan. The latter was always considered more sacred even by the eastern tribes themselves.