He shall be like a tree planted by the rivers of water.
The righteous man is not like a tombstone but like a tree. A tombstone is permanent, but it is dead permanence. A tree has living permanence, it is planted, not merely put, by the rivers of water.
The Psalmist said, “My heart is fixed.” Some saints have fixed heads, they are steadfast and unmovable, but it is the fixity of stubbornness and obstinacy. “Nothing is more like real conviction than simple obstinacy.” So much of orthodoxy is the tombstone kind. We tend to petrify. Religious movements run a certain course – a man, a movement, a machine, a monument. Churches tend to become like trees in the Petrified Forest instead of living trees by the rivers of water
Our faith, too, must be like seed, not sand, for living permanence endures because it perpetuates itself. A stone remains a stone. The Gospel reproduces itself from life to life. Christ lives from generation, not only in heaven but in the hearts of His people.