There is a river whose streams make glad the city of God, the holy habitation of the Most High. God is in the midst of her; she shall not be moved; God will help her when morning dawns.
The poetic image here captivates holy imagination for me. This psalm was probably meant to be a worship song at the temple. The whole concept of God habitating with people and dwelling in the midst of the city was known by the Jews at Mount Zion where the temple existed for the worship of Yahweh. This psalm my have been part of some regular temple festival, sung as pilgrims drew near the Temple Mount.
But what is celebrated is God's nearness. He was accessible. He could be worshiped at the temple where His presence dwelt in the holiest place. Worshipers could be in the place where God Himself dwelt and they could know Him in His nearness. That's something worth singing about!
And now since Christ has, by His death, torn the curtain separating God's presence from us, we know an even more intimate access to God. The river now flows, not in the midst of a city, but in my heart. He dwells within a temple not made of hands, but of my life. And this is true of every Christian. Any believer can know this. God is with us. God dwells in us. He will never leave us nor forsake us... forever!