The directions in the previous verses were meant to be only the first steps for the believers in their journey towards God and the commandments in them were meant for the control of the natural human desires and passions which the Promised Messiah has called the self that incites to evil. This is the first stage of the human development that differentiates human beings from animals.
Thus the Quran has given the believers some additional guidelines in this respect. Concerning women, it does not only direct them to hide their outer beauty, but it also teaches them not display their hidden beauty as well, so much so that we find that in the above mentioned verses, women are reminded to watch even their manner of walking and moving about. They should be careful with every aspect of their behaviour and actions. This is further elaborated in another place of the Holy Quran where Allah says:
O wives of the prophet you are not like any other woman if you are righteous. So be not soft in speech lest he in whose heart is a disease should feel tempted; and speak decent words.
And stay in your houses with dignity and display not your beauty like the displaying of the former days of ignorance and observe prayer and pay the Zakat and obey Allah and His Messenger. Surely, Allah desires to remove from you all uncleanliness, O members of the household, and purify you completely. (33:33-34)
Here the Quran has ended the commandments with the words: Surely Allah desires to remove from you all uncleanliness, O members of the household and purify you completely. This indicates that these teachings are completing the previous ones for the purpose of purifying the believing women. These verses address the women who have already taken the first step of educating their natural faculties and are now in the process of educating their moral state.
The verses address the wives of the Holy Prophet. But as the Holy Prophet is an exemplar for all Muslims, it is the custom of the Quran that what he is ordered to do is meant to be followed by all the other Muslims. In the same way his wives are taken as exemplars for all the Muslim women. It is also interesting to notice here that the women are addressed in this verse as wives to draw their attention to the fact that, to reach this stage, they need to become housewives. The words members of the household added towards end of the verses indicate that these directions are meant for the believing women who want to be counted among the members of the spiritual household of the Holy Prophet or, in other words, to be regarded as the believing women of a high spiritual status.
In these verses it is required from women to behave with dignity and talk in a formal manner when addressing men. This is another veil that should be observed between men and women. Islam discourages too much familiarity between the two sexes. This is intended to purify their thoughts and to protect women from slanderous tongues. It is clear that these teachings are meant for the well being of women and to remove any cause of inconvenience for them from its very roots.
These verses also encourage women to give their full attention to the discharge of their serious and important duties in the management of the household affairs and to looking after the children and bringing them up. It adds that this can be successfully achieved by observing the teachings of Islam and obeying God and His Messenger.
The real purpose of a woman staying in the house is explained in the verse that follows the previous verses where we read:
And remember what is rehearsed in your houses of the Signs of Allah and wisdom. Verily Allah is Subtle, All-Aware. (33:35)
This shows that the purpose of women staying in their houses is to enable them to make use of the spiritual provisions presented to them and to use them the best possible way to produce the best spiritual food for others.