Commentary for Psalms 119:3

Not only have they committed no injustice They are praiseworthy if all this is in them.

they walked in His ways Although they committed no injustice, their reward is incomplete unless they walked in His ways. And so he says (above 43:15): “Shun evil and do good.” Even though you shun evil, everything is not complete unless you do good. Midrash Aggadah.