Adam Clarke on Ezekiel 47:9

Every thing - whithersoever the rivers shall come, shall live - Life and salvation shall continually accompany the preaching of the Gospel; the death of sin being removed, the life of righteousness shall be brought in.

There shall be a very great multitude of fish - On the above plan this must refer to genuine converts to the Christian faith; true believers, who have got life and salvation by the streams of God's grace. The apostles were fishers of men; converts were the fish caught. See below. As the waters flow into the Dead Sea, where no fish, it is said, can live, its waters must be healed, that is, made capable of preserving life; and so its nature be thus far most surprisingly altered.