Then he said to me: “This water flows toward the eastern region, goes down into the valley, and enters the sea. When it reaches the sea, its waters are healed. And it shall be that every living thing that moves, wherever the rivers go, will live. There will be a very great multitude of fish, because these waters go there; for they will be healed, and everything will live wherever the river goes. [Ezekiel 47:8-9]
Ezekiel was looking into the future. Most commentaries agree that the waters symbolize the gospel of Christ reaching out to the world, starting from Jerusalem. Note the effects of the waters. It would heal, and give life to everything wherever it goes. Similarly, Christ is the Healer healing the people. His grace and His gospel give us life, eternal life. The later verses show how the banks of the river would flourish, just like wherever the gospel goes, lives are transformed.