9 And whence were you fed? And what pleased you, when he did not eat with you? “My eyes,” he says, “were upon such as are faithful in the land, that they might sit with me”. That is, that with Me they might be seated. In what sense are they “to sit”? “You shall sit on twelve thrones, judging the twelve tribes of Israel.” The faithful of the earth judge, for to them it is said, “Do you not know, that we shall judge angels?” “Whoso walks in a spotless way, he ministered unto me.” To “Me,” he says, not to himself. For many minister the Gospel, but unto themselves; because they seek their own things, not the things of Jesus Christ....
10. “The proud man has not dwelt in the midst of my house”. Understand this of the heart. The proud did not dwell in my heart: no such dwelt in my heart: for he hurried away from me. None but the meek and peaceful dwelt in my heart; the proud dwelt not there, for the unrighteous one dwells not in the heart of the righteous. Let the righteous be distant from you, I know not how many miles and stations: ye dwell together, if you have one heart. “The proud doer has not dwelt in the midst of my house: he that speaks unjust things has not directed in the sight of my eyes.” This is the spotless way, where we understand when the Lord comes unto us.
11. “In the morning I destroyed all the ungodly that were in the land. That I may root out all wicked doers from the city of the Lord”. This is obscure. There are then wicked doers in the city of the Lord, and they at present, seemingly, spared. Why so? Because it is the season of mercy: but that of judgment will come; for the Psalm thus began, “Of mercy and judgment will I sing unto You, O Lord.”...
Source: The Enarrations, or Expositions, on the Psalms (New Advent)