What does Revelation 22:1 mean?

A river as clear as crystal flows from the throne of God and the Lamb in New Jerusalem. Many of the judgments seen in the tribulation involved pollution of water. Ceremonial uncleanness was meant to symbolize moral filth. In the modern day, rivers and oceans are filled with trash and waste, but nothing unclean—physically or morally—can enter New Jerusalem (Revelation 21:27). The river that flows from the throne is perfect and pure. Fresh water will pour through the city.

Because it is the water of life and crystal clear, this river also symbolizes the nature of God and the Lamb. They are "holy, holy, holy," as the seraphim and the four living creatures declare (Isaiah 6:3; Revelation 4:8). Ezekiel 47:1, 12 describes a similar river that flows from the temple in Jerusalem. Alongside the river, Ezekiel saw all kinds of trees for food. The rivers seem similar, but they are different. The one the apostle John saw is in New Jerusalem. The one Ezekiel saw flows from the temple in the millennial Jerusalem. There is no temple in New Jerusalem (Revelation 21:22). However, both rivers are sourced in God.