That is a phrase that is left out of the Responsorial Psalm for today.  Psalm 3 consists of 8 verses in the Hebrew text.  The response for today uses every verse in the text except for one.  Why leave out one verse?  Because it reads:

Rise up, O LORD! Deliver me, O my God! For you strike all my enemies on the cheek; you break the teeth of the wicked. (Psa 3:7 NRS; Hebrew  3:8)

The first part of the Psalm sounds very comforting, but I suppose it is hard for modern readers to blend comfort with the mental image of God breaking someone’s teeth, even if they belong to one’s enemies.

The lectionary really does change the way that we read or experience texts.  I believe that seeing how the lectionary handles texts like this really reflects emphasis.  In a modern context, emphasis is more on comfort from God and less on revenge on enemies.  But, still there is the danger that construing texts in this way will give a false impression to modern worshipers of the Bible as a text that is not as problematic as many make it out to be.