‘And he showed me a river of water of life, bright as crystal, proceeding from the throne of God and of the Lamb, in the middle of its street. And on this side of the river and on that was the tree of life bearing twelve types of fruits, yielding its fruit every month, and the leaves of the tree were for the healing of the nations.'
This is a clear parallel with the original Paradise in Genesis 2 where a river flowed through the garden, and also clearly has in mind the river flowing from the Temple of God in Ezekiel 47 on. The river is clean and totally pure, it comes from God's throne, Who is the source of all life, and it feeds the tree of life which bears fruit constantly for all. It is the river ‘whose streams make glad the city of God' (Psalms 46:4). Both the river of life (compare Revelation 7:17; Revelation 21:6 and see John 4:14; John 6:35) and the tree of life (see Revelation 2:7) are symbols of the eternal life received from God.
In John 7:38 we are specifically told that the rivers of living water refer to the Spirit of God. Thus central to the city of God is the Spirit of God. It is He Who is its life source. His life runs through it. The tree of life is on both sides of the river, it has thus reproduced itself. There are a number of offshoots and there is sufficient for all. The eternal life that God's people have received is continually and eternally nurtured. The twelve types of fruit show that all of the ‘twelve tribes' (the people of God) are catered for (see Ezekiel 47:12). (The literalists, of course, have to exclude the tribe of Dan).
‘The leaves of the tree were for the healing of the nations' (compare Ezekiel 47:12). Note the past tense. The nations who have responded are now healed because they partook of the river and tree of life in Christ. The leaves enable them to look back and remind themselves of the healing they had once known through the activity of the Spirit of God, and what blessing they have now received. God had made full provision for their healing. We may see it as a reminder that there is no illness here. So Paradise is now restored.
Alternately we may see ‘healing' as signifying the ‘maintenance of health'. After all, this is the tree of life. The thought may be that just as human bodies constantly need a process of maintenance and restoration (that is why we need vitamins) so God has made continual provision for the health of His people. Again the idea is simply that there is no lack of total health there. All that is needed for full health is provided.
We must of course recognise the symbolism of the whole. In the resurrection world there will be no physical trees and we will have spiritual bodies (whatever they are). We can have no conception of the realities involved but we can be sure that they will provide all that we need. We note again that there is only ‘one street', a symbol of the unity of God's people in the New Jerusalem.