For you strike all my enemies on the cheek;
you break the teeth of the wicked.
Peter C. Craigie (1938-1985), Psalms 1-50
(Waco: Word Books, 1983), p. 75:
The psalmist prays that God would smite his enemies "on the cheek" (3:8c). The words
are symbolic; to smite someone on the cheek was to administer a gross insult (cf. 1 Kgs
22:24; Job 16:10; Lam 3:30). As the psalmist had been insulted by the words of his
enemies (3:3b), so now he prays for an insult to be administered to them. The parallel
line (3:8d) takes the thought further. He prays that God would "smash the teeth of wicked
men"; although the words have been interpreted as the imagery of savage beasts rendered
harmless through fractured teeth, it is possible that their primary significance is with
respect to speechlessness. The enemies had spoken wicked words (3:3d), but mouths
cluttered with shattered teeth could no longer voice their enmity....The words of v 8cd seem at first vindictive and harsh, with respect to the enemy. Yet in their transformation, it is not that one prays for God's action against the enemy as such, but against the evil which they speak and do.