Men are in charge of women, because Allah made men to be better than women. Refuse to have sex with women from whom you fear rebellion, and scourge them. 4:34
PICKTHAL: Men are in charge of women, because Allah hath made the one of them to excel the other, and because they spend of their property (for the support of women). So good women are the obedient, guarding in secret that which Allah hath guarded. As for those from whom ye fear rebellion, admonish them and banish them to beds apart, and scourge them. Then if they obey you, seek not a way against them. Lo! Allah is ever High, Exalted, Great.
If you are in a habit of scourging a woman then killing is a common second step.
Here is a Quranic verse in which "idreb" is used:
8:12 - ""Strike" off their heads, "strike" off the very tips of their fingers!"
By striking on the head of a person is not less than killing (its most likely that a person cam die of head injury)