v. 1: David does not here accuse strangers or foreigners, but informs us that this deluge of iniquity prevailed in the Church of God. - John Calvin.
v.5: What's truly lacking beyond the mask of godliness and faithfulness.
v.5-6: God is the only ultimate refuge. Not fellow men.
v.8: This verse is not an affirmation of an undesirable ending. But the affirmation of the first verse: That these supposedly godly man and faithful walking on every side and being exalted. The structure of the psalm is not to place the ending chronologically, but like the mountain, the chief end is at the peak in the middle of the song, so that the plea for help from the beginning is still being reminded at the end.