In the last resort, the principal wisdom of the psalm can be reduced to v 2; the prosperity and happiness of the righteous depends upon their finding “delight” in the Lord’s Torah. But how is such delight to be found? In practical terms, it is achieved by constant meditation upon the Torah (v 2b), which is God’s instruction. As instruction, it contains guidance from the Creator as to the meaning of creation. Life is lived in futility if its fundamental purpose is never discovered. It is the meaning of human existence which is enshrined in the Torah, and it is the discovery of that meaning which flows from meditation upon Torah.

PETER C. CRAIGIE AND MARVIN TATE, PSALMS 1-50, VOLUME 19: SECOND EDITION (WORD BIBLICAL COMMENTARY), 61.