"Men are the protectors of women because of the greater preference that God has given to some of them and because they financially support them. Among virtuous women are those who are steadfast in prayer and dependable in keeping the secrets that God has protected. Admonish women who disobey (God's laws), do not sleep with them and beat them. If they obey (the laws of God), do not try to find fault in them. God is High and Supreme." (4:34)
The verse 4:33 talks of men's obligation to women, i.e. the responsibility of maintainance. To avoid disharmony, verse 4:34 suggests steps to be taken to resolve disputes. As Allama Tabatabai remarks in his Tafsir: The steps are to be taken gradually and in a particular order. If the wife is of ill-conduct then 1) she is to be verbally advised and admonished. If that doesn't work, then 2) suspend sexual contact by say refusing to share the same bed and only, as a last resort, very light form of physical correction is to be undertaken. Allama Tabrisi in his Majma al-Bayan quotes a tradition from Imam al-Baqir (A.S.) stating that this should be done with a miswak (kind of toothbrush in modern times). There is absolutely no justification in this for the domestic abuse or violence that many Muslim men resort to these days. Indeed, all commentators are in agreement that the third form of corrective measure should be undertaken only as a last resort and should be very mild. It should also be noted that the Qur'an gives precedence to the state of order and emphasizes the importance of retaining it. Also, even if the third solution is reached, it should not lead to conjugal violence or struggle, rather the whole objective of the verse has to be borne in mind, that of returning to marital harmony. AS verse 4:128 states, "Peace is better" i.e. peace and making amends are the goals, not violence and disharmony. The second solution (beds apart) also suggests that before the third step is reached, there is a need for 'a cooling-off period'. Most Muslim men who resort to violence never follow the steps required in the Qur'an. > >For further details, pls see Allama Tabataba'i's Tafsir al-Mizan, Tabrisi's Majma' al-Bayan. Amin Wadud-Muhsin also has a very interesting book entitled Qur'an and Woman.