7. Arise, O Lord—God is figuratively represented as asleep to denote His apparent indifference (Ps 7:6). The use of "cheekbone" and "teeth" represents his enemies as fierce, like wild beasts ready to devour (Ps 27:2), and smiting their cheekbone (1Ki 22:24) denotes violence and insult.
thou hast broken—God took his part, utterly depriving the enemy of power to injure.