The Psalms are packed with vivid word pictures and simple metaphors that make their messages immediately accessible and applicable. The person who loves and concentrates on God’s words and ways is compared to a fruitful tree here—only one of several places in the Old Testament where God’s people are compared to sturdy trees (Isa 44:2-4; Jer 17:7-8).
In a description of the coming Messiah, Jesus Christ himself is depicted as a “splendid cedar” that will give shelter and shade to all who take refuge in him (Eze 17:22-24). The tree metaphor’s richness is evident when we consider the elements of a healthy tree: the deep roots that feed and stabilize it, the branches that gracefully offer shade, the leaves that often possess healing properties, the fruit that nourishes.
A blessed person is one who is deeply rooted in the soil of God’s Word and who draws sustenance from his living water.
(General Editor Jean E. Syswerda, NIV Women of Faith Study Bible, Zondervan Publishing House, Grand Rapids, Mischigan, 2001, pg 858)