1 Chronicles 5:9

He inhabited, i.e. the tribe of Reuben. From the river Euphrates; from Jordan and the wilderness beyond it unto Euphrates. Or, of the wilderness, which lies towards or reacheth to the river Euphrates, namely, the great wilderness of Kedemoth, Deuteronomy 2:26, which was extended far and wide towards Euphrates; for that was the eastern border of Reuben's possession, and not Euphrates, to which their habitation never reached. Their cattle were multiplied; which forced them to enlarge their habitation as far as they could eastward towards Euphrates.