“The righteous are introduced as the “blessed” or “happy” (see further H. Cazelles, TDOT I, 445–48). Their happy estate is not something given automatically by God, but is a direct result of their activity. A person can be happy, from a negative perspective, by avoiding the advice, the life style and the assembly of wicked persons (v 1). The three parallel lines of v 1 are poetically synonymous and thus all describe in slightly different ways the evil company which should be avoided by the righteous. Though the three lines, taken together, provide a full picture of what is to be avoided, it would be stretching the text beyond its natural meaning to see in these lines three distinct phases in the deterioration of a person’s conduct and character (see further G. W. Anderson, VT 24 [1974] 231–33). The righteous person avoids all the dimensions of the way of the wicked; therein lies the source of blessedness or happiness

PETER C. CRAIGIE AND MARVIN TATE, PSALMS 1-50, VOLUME 19: SECOND EDITION (WORD BIBLICAL COMMENTARY), 60.