“The righteous flourish like the palm tree and grow like a cedar in Lebanon. They are planted in the house of the LORD; they flourish in the courts of our God” (v12-13). The psalmist said that even though evildoers spring up and appear to “flourish” (v7), their purpose and eventual end (destruction) is the opposite of the righteous. Being “planted in the house of the Lord” means that we have become part of God’s family. We have submitted our goals and energies to His wonderful work (v4-5), and so we flourish within His kingdom.
Even when our physical strength diminishes, we can be “ever full of sap and green” (v14), fruitful, because we are living for God’s purposes.