Like a morning bird song, or Paul's letter to the Philippians, this psalm rings with pure notes of joy. A communal celebration on the Sabbath that could never grow old, body and soul rejoicing in God. Joy is buoyant, never weighed down by the storms of this world, yet weighty as it's rooted not in fleeting circumstances, but in God, and in being a specific kind of person.
As if to outline this, the psalm provides a contrast between the senseless or "stupid " person and the righteous. The "senseless" person doesn't sense that what looms large in his mind as the definition of flourishing is really only the quick fix, as tall and permanent as the blades of grass.
There are two kinds of flourishing, the psalmist says: the quick grass kind, and the slow-growing-giant-palm-tree kind. And when you're planted in God, right in his temple, this God-given flourishing is majestic and permanent. As the giant palm tree or cedar is higher than the grass or "as the heavens are higher than the earth, so are my ways higher than your ways, my thoughts higher than your thoughts." (Isaiah 55 - and He was specifically talking about a work of grace in our hearts in that instance). God is doing a work in you. He is taking great care to make this never-ending greenness, this never-stopping fruitfulness in you.
Yes, there are enemies to joy. But they are only like the water that Elijah had poured on the alter, when the fire still lit and burned all the brighter. The fire WILL burn strong, and joy WILL bubble up. The kind of flourishing that God is working on may seem precarious but it's actually as immovable and strong as those massive palm trees we had back in Africa. Yes, it is good to give thanks to the Lord.
Matt P