11 But the fact that he has not walked in the counsel of the ungodly, nor stood in the way of sinners, nor sat in the seat of pestilence, does not constitute the perfection of the man's happiness. For the belief that one God is the Creator of the world, the avoidance of sin by the pursuit of unassuming goodness, the preference of the tranquil leisure of private life to the grandeur of public position— all this may be found even in a pagan. But here the Prophet, in portraying in the likeness of God the man that is perfect— one who may serve as a noble example of eternal happiness— points to the exercise by him of no commonplace virtues, and to the words, But his will has been in the Law of the Lord, for the attainment of perfect happiness.
To refrain from what has gone before is useless unless his mind be set on what follows, But his will has been in the Law of the Lord. The Prophet does not look for fear. The majority of men are kept within the bounds of Law by fear; the few are brought under the Law by will: for it is the mark of fear not to dare to omit what it is afraid of, but of perfect piety to be ready to obey commands. This is why that man is happy whose will, not whose fear, is in the Law of God.
Source: Homilies on the Psalms (New Advent)