Why Do Women Cover Their Hair?
Question

Why do Muslim women cover their hair and what happens if they do or if they don’t?
Praise be to Allah.Muslim women cover their hair because Allah has commanded them to do so, and it is not permissible for them to go against what He says and disobey His command. Allah has only commanded them to do this because there is great wisdom in it. 
Part of that wisdom is that it protects a woman’s honour from the “human wolves” who are looking for easy prey to attack and devour, and a morsel cannot be eaten unless it is prepared and ready – which is what we see in those woman who make a display of themselves, who by their appearance are calling those wolves to come and take whatever they want!
Confirmation of this is to be found in the words of Allah (interpretation of the meaning):
“… That will be better, that they should be known (as free respectable women) so as not to be annoyed…” [al-Ahzab 33:59]. 
If a woman covers herself , then immoral and corrupt men will know that this is not part of their prey, thus Allah will protect them and take care of them.
Allah and His Messenger (peace and blessings of Allah be upon him) have issued a stern warning to women who make a display of themselves. An example of this is:
Abu Hurayrah said: The Messenger of Allah (peace and blessings of Allaah be upon him) said: “There are two types of the people of Hell whom I have not seen: a people with whips like the tails of cattle, with which they beat the people, and women who are clothed but naked, walking with an enticing gait and with their heads looking like the humps of camels, leaning to one side. They will not enter Paradise and will not even smell its fragrance, although its fragrance can be detected from such and such a distance.” (Narrated by Muslim, 2128).
A woman [or a man] should not try to comprehend Islamic rulings with her reason – which is unable to encompass the wisdom of Shari’ah. She should know that whatever Allah has enjoined upon her contains nothing but goodness and happiness for her, her family and society as a whole. 
It is known that a woman’s uncovering her hair makes her more attractive to men, which could lead to them forming hopes about her and committing immoral actions. 
Islam wants society to be clean, with no provocation of desires, outrage or uncovering of women’s charms – which include their hair – which can lead to others being tempted by her and which opens the door to evil and its people.
We need to point out again that Islam means submitting to Allah. The believer follows the command of Allah even if he does not know the wisdom behind it or he does not find anything to convince his reason for it, because his obedience of his Lord and his submission to His command take priority over all other things, and worship is based on obedience and submission.
We ask Allah to show us the truth and help us to follow it, and to show us falsehood and help us to avoid it.
And Allah knows best.