Keil & Delitzsch

The righteous, who go astray according to the judgment of the world, thus arrive at a goal from which their way appears in a very different light. "The path that the righteous man takes is smoothness; Thou makest the course of the righteous smooth." ישׁר is an accusative predicate: Thou rollest it, i.e., Thou smoothest it, so that it is just as if it had been bevelled with a rule, and leads quite straight (on the derivative peles, a level, see at Job 37:16) and without interruption to the desired end. The song has here fallen into the language of a mashal of Solomon (vid., Pro 4:26; Pro 5:6, Pro 5:21). It pauses here to reflect, as if at the close of a strophe.