Albert Barnes Commentary Ezekiel 47:5

"Afterward he measured a thousand; [and it was] a river that I could not pass through; for the waters were risen, waters to swim in, a river that could not be passed through." — Ezekiel 47:5 (ASV)

The rivers in Palestine were for the most part mere watercourses, dry in summer, in winter carrying the water along the wadys to the sea. The river of the vision is to have a continuous flow.

Waters to swim in - When under Constantine the Roman empire had become Christian, the Church may be contemplated as the full river, to flow on through time until the final completion of Isaiah’s prophecy (Isaiah 11:9).