Our text uses the singular, to refer to a single tree. So our thoughts go directly to the tree of life in the Garden of Eden (Genesis 2:9; Genesis 3:24) and its function in the garden (about which so much could be written and perhaps more could be speculated). It is fitting to notice the following:
This tree is life-giving, just as the water of the river was life-giving (Revelation 22:1).
Though the reference is singular (that is, one tree), the passage tells us the
tree
is on both sides of the river. So we should understand the singular to be collective (hence many trees), with the singular drawing attention to the single purpose of the trees (instead of its number), that is, its life-giving quality.The tree bears multiple fruits (
twelve kinds
), monthly (= twelve times per year), again drawing attention to its essential life-giving quality.
Adding this together, we are to understand the symbolism of this life-giving tree to denote the richness that results from the river of life-giving water nourishing this life-giving tree. The city of God provides a richness greater than the Promised Land of Canaan, a richness akin to Paradise (Genesis 2:9).
2 through the middle of the street of the city; also, on either side of the river, the tree of life with its twelve kinds of fruit, yielding its fruit each month. The leaves of the tree were for the healing of the nations.