Charles Ellicott Commentary Ezra 4:16

"We certify the king that, if this city be builded, and the walls finished, by this means thou shalt have no portion beyond the River." — Ezra 4:16 (ASV)

No portion on this side the river. —The same unscrupulous use of language: that is, if the river Euphrates is meant. In the days of Solomon, and once or twice subsequently, the Israelites had advanced towards the river, but it was not likely that they would ever do so again. The letter may, however, have been intended to suggest loosely that Jerusalem might become a centre of general disaffection.