In "God's Word for Today" Steve Oliver writes
At last, we come to the end of history as we know it, and yet it is but the first instant of eternity. As the angel continued the “tour” of New Jerusalem, John beheld other wonders — a river of life pouring forth from the throne of God, and the trees of life lining the river on both sides. Human history began in a garden paradise, and here God has brought it full circle, back to the ultimate garden paradise of which Eden was but a dim reflection. Here, rather than living with the possibility of expulsion for disobedience, the saints will reign “for ever and ever.”
Source: Christ, the Triumphant Lord: Adult Teacher's Insights, page 75.