The requirements of the Shari'a are many and varied so only some general outlines can be mentioned here.
There are varying degrees to which one is required to perform different acts.
Actions can be:
i) obligatory (fard) - ie. prayer
ii) commendable (sunna) - ie. hospitality
iii) allowed (halal) - ie. kindness to animals
iv) discouraged (makruh) - ie. divorce
v) forbidden (haram) - ie. drinking of alcohol
Qur'anic law is very thorough about the various details of civil life, for example:
Dietary and Health Requirements
Only certain kinds of food can be eaten. Pork for example is forbidden. All meat must be slaughtered in a particular way (halal). There is a strong requirement for cleanliness and if possible one should always wash in running water.
Relationships
Islam is by no means prudish about sex or sexual relations between man and woman. However, it requires modesty so that one does not become over libidinous and forget ones submission to Allah. For this reason it requires that sexual temptation be kept to a minimum and hence that women should be modestly dressed. Scholars debate whether this means being covered from head to toe although at 24.30-31 the Qur'an states that in order to turn eyes from temptation women should "draw veils over their bosoms and not reveal their beauty except to their husbands".
The justification for polygamy (having more than one wife) is also ambiguous. At one point the Qur'an seems to indicate that a man can have up to four wives, provided that all are treated equally. Elsewhere however (4.129), it states that it is impossible to treat all wives equally, hence (by implication) no one should take more than one wife.
